1616190240
Top 100 Questions You Must Prepare For Your Next Angular Interview (1–45)
Angular Interview Questions 2021-Part 1 (1–45)
Recently, I was trying to prepare myself for the upcoming interviews and it was a bit tough to search in google and open link and see same questions each and every time so I thought of sharing what I have found and what is most common questions someone should know if they are preparing for an interview.
Below are the most common interview questions asked in Latest Angular Interviews. These Angular Interview questions and answers help to prepare for Angular developer interviews from junior to senior levels. Moreover, this article covers the basics to advance angular interview questions which you must prepare in 2021.
1. What is the difference between constructor and ngOnInit?
2. What is the difference between components and directives?
3. What is the difference between ElementRef, TemplateRef, and viewContainerRef?
4. What is the difference between ng-content,ng-template, and ng-container?
5. What is the difference between view-child and content-child?
6. What is the difference between component view, host view, and embedded view?
7. What is the difference between debounce time and throttle time?
8. What is the difference between forEach and map?
9. What is the difference between ng-content and ng-templateoutlet?
10. What is the difference between forchild vs forroot?
11. Why we use pipe operators in RXJS. What is the use of it?
12. What is the difference between using the Async pipe vs the subscribe function in the Angular application?
13. What is the difference between promise and observable?
14. What is the difference between Event Emitter and Subjects?
15. What is the difference between Observable and Subject?
#angular #typescript #web-development #programming #rxjs
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A Pure PHP Implementation Of The MessagePack Serialization Format
msgpack.php
A pure PHP implementation of the MessagePack serialization format.
Features
- Fully compliant with the latest MessagePack specification
- Supports streaming unpacking
- Supports unsigned 64-bit integers handling
- Supports object serialization
- Fully tested
- Relatively fast
Installation
The recommended way to install the library is through Composer:
composer require rybakit/msgpack
Usage
Packing
To pack values you can either use an instance of a Packer:
$packer = new Packer();
$packed = $packer->pack($value);
or call a static method on the MessagePack class:
$packed = MessagePack::pack($value);
In the examples above, the method pack automatically packs a value depending on its type. However, not all PHP types can be uniquely translated to MessagePack types. For example, the MessagePack format defines map and array types, which are represented by a single array type in PHP. By default, the packer will pack a PHP array as a MessagePack array if it has sequential numeric keys, starting from 0 and as a MessagePack map otherwise:
$mpArr1 = $packer->pack([1, 2]); // MP array [1, 2]
$mpArr2 = $packer->pack([0 => 1, 1 => 2]); // MP array [1, 2]
$mpMap1 = $packer->pack([0 => 1, 2 => 3]); // MP map {0: 1, 2: 3}
$mpMap2 = $packer->pack([1 => 2, 2 => 3]); // MP map {1: 2, 2: 3}
$mpMap3 = $packer->pack(['a' => 1, 'b' => 2]); // MP map {a: 1, b: 2}
However, sometimes you need to pack a sequential array as a MessagePack map. To do this, use the packMap method:
$mpMap = $packer->packMap([1, 2]); // {0: 1, 1: 2}
Here is a list of type-specific packing methods:
$packer->packNil(); // MP nil
$packer->packBool(true); // MP bool
$packer->packInt(42); // MP int
$packer->packFloat(M_PI); // MP float (32 or 64)
$packer->packFloat32(M_PI); // MP float 32
$packer->packFloat64(M_PI); // MP float 64
$packer->packStr('foo'); // MP str
$packer->packBin("\x80"); // MP bin
$packer->packArray([1, 2]); // MP array
$packer->packMap(['a' => 1]); // MP map
$packer->packExt(1, "\xaa"); // MP ext
Check the "Custom types" section below on how to pack custom types.
Packing options
The Packer object supports a number of bitmask-based options for fine-tuning the packing process (defaults are in bold):
| Name | Description |
|---|---|
FORCE_STR | Forces PHP strings to be packed as MessagePack UTF-8 strings |
FORCE_BIN | Forces PHP strings to be packed as MessagePack binary data |
DETECT_STR_BIN | Detects MessagePack str/bin type automatically |
FORCE_ARR | Forces PHP arrays to be packed as MessagePack arrays |
FORCE_MAP | Forces PHP arrays to be packed as MessagePack maps |
DETECT_ARR_MAP | Detects MessagePack array/map type automatically |
FORCE_FLOAT32 | Forces PHP floats to be packed as 32-bits MessagePack floats |
FORCE_FLOAT64 | Forces PHP floats to be packed as 64-bits MessagePack floats |
The type detection mode (
DETECT_STR_BIN/DETECT_ARR_MAP) adds some overhead which can be noticed when you pack large (16- and 32-bit) arrays or strings. However, if you know the value type in advance (for example, you only work with UTF-8 strings or/and associative arrays), you can eliminate this overhead by forcing the packer to use the appropriate type, which will save it from running the auto-detection routine. Another option is to explicitly specify the value type. The library provides 2 auxiliary classes for this,MapandBin. Check the "Custom types" section below for details.
Examples:
// detect str/bin type and pack PHP 64-bit floats (doubles) to MP 32-bit floats
$packer = new Packer(PackOptions::DETECT_STR_BIN | PackOptions::FORCE_FLOAT32);
// these will throw MessagePack\Exception\InvalidOptionException
$packer = new Packer(PackOptions::FORCE_STR | PackOptions::FORCE_BIN);
$packer = new Packer(PackOptions::FORCE_FLOAT32 | PackOptions::FORCE_FLOAT64);
Unpacking
To unpack data you can either use an instance of a BufferUnpacker:
$unpacker = new BufferUnpacker();
$unpacker->reset($packed);
$value = $unpacker->unpack();
or call a static method on the MessagePack class:
$value = MessagePack::unpack($packed);
If the packed data is received in chunks (e.g. when reading from a stream), use the tryUnpack method, which attempts to unpack data and returns an array of unpacked messages (if any) instead of throwing an InsufficientDataException:
while ($chunk = ...) {
$unpacker->append($chunk);
if ($messages = $unpacker->tryUnpack()) {
return $messages;
}
}
If you want to unpack from a specific position in a buffer, use seek:
$unpacker->seek(42); // set position equal to 42 bytes
$unpacker->seek(-8); // set position to 8 bytes before the end of the buffer
To skip bytes from the current position, use skip:
$unpacker->skip(10); // set position to 10 bytes ahead of the current position
To get the number of remaining (unread) bytes in the buffer:
$unreadBytesCount = $unpacker->getRemainingCount();
To check whether the buffer has unread data:
$hasUnreadBytes = $unpacker->hasRemaining();
If needed, you can remove already read data from the buffer by calling:
$releasedBytesCount = $unpacker->release();
With the read method you can read raw (packed) data:
$packedData = $unpacker->read(2); // read 2 bytes
Besides the above methods BufferUnpacker provides type-specific unpacking methods, namely:
$unpacker->unpackNil(); // PHP null
$unpacker->unpackBool(); // PHP bool
$unpacker->unpackInt(); // PHP int
$unpacker->unpackFloat(); // PHP float
$unpacker->unpackStr(); // PHP UTF-8 string
$unpacker->unpackBin(); // PHP binary string
$unpacker->unpackArray(); // PHP sequential array
$unpacker->unpackMap(); // PHP associative array
$unpacker->unpackExt(); // PHP MessagePack\Type\Ext object
Unpacking options
The BufferUnpacker object supports a number of bitmask-based options for fine-tuning the unpacking process (defaults are in bold):
| Name | Description |
|---|---|
BIGINT_AS_STR | Converts overflowed integers to strings [1] |
BIGINT_AS_GMP | Converts overflowed integers to GMP objects [2] |
BIGINT_AS_DEC | Converts overflowed integers to Decimal\Decimal objects [3] |
1. The binary MessagePack format has unsigned 64-bit as its largest integer data type, but PHP does not support such integers, which means that an overflow can occur during unpacking.
2. Make sure the GMP extension is enabled.
3. Make sure the Decimal extension is enabled.
Examples:
$packedUint64 = "\xcf"."\xff\xff\xff\xff"."\xff\xff\xff\xff";
$unpacker = new BufferUnpacker($packedUint64);
var_dump($unpacker->unpack()); // string(20) "18446744073709551615"
$unpacker = new BufferUnpacker($packedUint64, UnpackOptions::BIGINT_AS_GMP);
var_dump($unpacker->unpack()); // object(GMP) {...}
$unpacker = new BufferUnpacker($packedUint64, UnpackOptions::BIGINT_AS_DEC);
var_dump($unpacker->unpack()); // object(Decimal\Decimal) {...}
Custom types
In addition to the basic types, the library provides functionality to serialize and deserialize arbitrary types. This can be done in several ways, depending on your use case. Let's take a look at them.
Type objects
If you need to serialize an instance of one of your classes into one of the basic MessagePack types, the best way to do this is to implement the CanBePacked interface in the class. A good example of such a class is the Map type class that comes with the library. This type is useful when you want to explicitly specify that a given PHP array should be packed as a MessagePack map without triggering an automatic type detection routine:
$packer = new Packer();
$packedMap = $packer->pack(new Map([1, 2, 3]));
$packedArray = $packer->pack([1, 2, 3]);
More type examples can be found in the src/Type directory.
Type transformers
As with type objects, type transformers are only responsible for serializing values. They should be used when you need to serialize a value that does not implement the CanBePacked interface. Examples of such values could be instances of built-in or third-party classes that you don't own, or non-objects such as resources.
A transformer class must implement the CanPack interface. To use a transformer, it must first be registered in the packer. Here is an example of how to serialize PHP streams into the MessagePack bin format type using one of the supplied transformers, StreamTransformer:
$packer = new Packer(null, [new StreamTransformer()]);
$packedBin = $packer->pack(fopen('/path/to/file', 'r+'));
More type transformer examples can be found in the src/TypeTransformer directory.
Extensions
In contrast to the cases described above, extensions are intended to handle extension types and are responsible for both serialization and deserialization of values (types).
An extension class must implement the Extension interface. To use an extension, it must first be registered in the packer and the unpacker.
The MessagePack specification divides extension types into two groups: predefined and application-specific. Currently, there is only one predefined type in the specification, Timestamp.
Timestamp
The Timestamp extension type is a predefined type. Support for this type in the library is done through the TimestampExtension class. This class is responsible for handling Timestamp objects, which represent the number of seconds and optional adjustment in nanoseconds:
$timestampExtension = new TimestampExtension();
$packer = new Packer();
$packer = $packer->extendWith($timestampExtension);
$unpacker = new BufferUnpacker();
$unpacker = $unpacker->extendWith($timestampExtension);
$packedTimestamp = $packer->pack(Timestamp::now());
$timestamp = $unpacker->reset($packedTimestamp)->unpack();
$seconds = $timestamp->getSeconds();
$nanoseconds = $timestamp->getNanoseconds();
When using the MessagePack class, the Timestamp extension is already registered:
$packedTimestamp = MessagePack::pack(Timestamp::now());
$timestamp = MessagePack::unpack($packedTimestamp);
Application-specific extensions
In addition, the format can be extended with your own types. For example, to make the built-in PHP DateTime objects first-class citizens in your code, you can create a corresponding extension, as shown in the example. Please note, that custom extensions have to be registered with a unique extension ID (an integer from 0 to 127).
More extension examples can be found in the examples/MessagePack directory.
To learn more about how extension types can be useful, check out this article.
Exceptions
If an error occurs during packing/unpacking, a PackingFailedException or an UnpackingFailedException will be thrown, respectively. In addition, an InsufficientDataException can be thrown during unpacking.
An InvalidOptionException will be thrown in case an invalid option (or a combination of mutually exclusive options) is used.
Tests
Run tests as follows:
vendor/bin/phpunit
Also, if you already have Docker installed, you can run the tests in a docker container. First, create a container:
./dockerfile.sh | docker build -t msgpack -
The command above will create a container named msgpack with PHP 8.1 runtime. You may change the default runtime by defining the PHP_IMAGE environment variable:
PHP_IMAGE='php:8.0-cli' ./dockerfile.sh | docker build -t msgpack -
See a list of various images here.
Then run the unit tests:
docker run --rm -v $PWD:/msgpack -w /msgpack msgpack
Fuzzing
To ensure that the unpacking works correctly with malformed/semi-malformed data, you can use a testing technique called Fuzzing. The library ships with a help file (target) for PHP-Fuzzer and can be used as follows:
php-fuzzer fuzz tests/fuzz_buffer_unpacker.php
Performance
To check performance, run:
php -n -dzend_extension=opcache.so \
-dpcre.jit=1 -dopcache.enable=1 -dopcache.enable_cli=1 \
tests/bench.php
Example output
Filter: MessagePack\Tests\Perf\Filter\ListFilter
Rounds: 3
Iterations: 100000
=============================================
Test/Target Packer BufferUnpacker
---------------------------------------------
nil .................. 0.0030 ........ 0.0139
false ................ 0.0037 ........ 0.0144
true ................. 0.0040 ........ 0.0137
7-bit uint #1 ........ 0.0052 ........ 0.0120
7-bit uint #2 ........ 0.0059 ........ 0.0114
7-bit uint #3 ........ 0.0061 ........ 0.0119
5-bit sint #1 ........ 0.0067 ........ 0.0126
5-bit sint #2 ........ 0.0064 ........ 0.0132
5-bit sint #3 ........ 0.0066 ........ 0.0135
8-bit uint #1 ........ 0.0078 ........ 0.0200
8-bit uint #2 ........ 0.0077 ........ 0.0212
8-bit uint #3 ........ 0.0086 ........ 0.0203
16-bit uint #1 ....... 0.0111 ........ 0.0271
16-bit uint #2 ....... 0.0115 ........ 0.0260
16-bit uint #3 ....... 0.0103 ........ 0.0273
32-bit uint #1 ....... 0.0116 ........ 0.0326
32-bit uint #2 ....... 0.0118 ........ 0.0332
32-bit uint #3 ....... 0.0127 ........ 0.0325
64-bit uint #1 ....... 0.0140 ........ 0.0277
64-bit uint #2 ....... 0.0134 ........ 0.0294
64-bit uint #3 ....... 0.0134 ........ 0.0281
8-bit int #1 ......... 0.0086 ........ 0.0241
8-bit int #2 ......... 0.0089 ........ 0.0225
8-bit int #3 ......... 0.0085 ........ 0.0229
16-bit int #1 ........ 0.0118 ........ 0.0280
16-bit int #2 ........ 0.0121 ........ 0.0270
16-bit int #3 ........ 0.0109 ........ 0.0274
32-bit int #1 ........ 0.0128 ........ 0.0346
32-bit int #2 ........ 0.0118 ........ 0.0339
32-bit int #3 ........ 0.0135 ........ 0.0368
64-bit int #1 ........ 0.0138 ........ 0.0276
64-bit int #2 ........ 0.0132 ........ 0.0286
64-bit int #3 ........ 0.0137 ........ 0.0274
64-bit int #4 ........ 0.0180 ........ 0.0285
64-bit float #1 ...... 0.0134 ........ 0.0284
64-bit float #2 ...... 0.0125 ........ 0.0275
64-bit float #3 ...... 0.0126 ........ 0.0283
fix string #1 ........ 0.0035 ........ 0.0133
fix string #2 ........ 0.0094 ........ 0.0216
fix string #3 ........ 0.0094 ........ 0.0222
fix string #4 ........ 0.0091 ........ 0.0241
8-bit string #1 ...... 0.0122 ........ 0.0301
8-bit string #2 ...... 0.0118 ........ 0.0304
8-bit string #3 ...... 0.0119 ........ 0.0315
16-bit string #1 ..... 0.0150 ........ 0.0388
16-bit string #2 ..... 0.1545 ........ 0.1665
32-bit string ........ 0.1570 ........ 0.1756
wide char string #1 .. 0.0091 ........ 0.0236
wide char string #2 .. 0.0122 ........ 0.0313
8-bit binary #1 ...... 0.0100 ........ 0.0302
8-bit binary #2 ...... 0.0123 ........ 0.0324
8-bit binary #3 ...... 0.0126 ........ 0.0327
16-bit binary ........ 0.0168 ........ 0.0372
32-bit binary ........ 0.1588 ........ 0.1754
fix array #1 ......... 0.0042 ........ 0.0131
fix array #2 ......... 0.0294 ........ 0.0367
fix array #3 ......... 0.0412 ........ 0.0472
16-bit array #1 ...... 0.1378 ........ 0.1596
16-bit array #2 ........... S ............. S
32-bit array .............. S ............. S
complex array ........ 0.1865 ........ 0.2283
fix map #1 ........... 0.0725 ........ 0.1048
fix map #2 ........... 0.0319 ........ 0.0405
fix map #3 ........... 0.0356 ........ 0.0665
fix map #4 ........... 0.0465 ........ 0.0497
16-bit map #1 ........ 0.2540 ........ 0.3028
16-bit map #2 ............. S ............. S
32-bit map ................ S ............. S
complex map .......... 0.2372 ........ 0.2710
fixext 1 ............. 0.0283 ........ 0.0358
fixext 2 ............. 0.0291 ........ 0.0371
fixext 4 ............. 0.0302 ........ 0.0355
fixext 8 ............. 0.0288 ........ 0.0384
fixext 16 ............ 0.0293 ........ 0.0359
8-bit ext ............ 0.0302 ........ 0.0439
16-bit ext ........... 0.0334 ........ 0.0499
32-bit ext ........... 0.1845 ........ 0.1888
32-bit timestamp #1 .. 0.0337 ........ 0.0547
32-bit timestamp #2 .. 0.0335 ........ 0.0560
64-bit timestamp #1 .. 0.0371 ........ 0.0575
64-bit timestamp #2 .. 0.0374 ........ 0.0542
64-bit timestamp #3 .. 0.0356 ........ 0.0533
96-bit timestamp #1 .. 0.0362 ........ 0.0699
96-bit timestamp #2 .. 0.0381 ........ 0.0701
96-bit timestamp #3 .. 0.0367 ........ 0.0687
=============================================
Total 2.7618 4.0820
Skipped 4 4
Failed 0 0
Ignored 0 0
With JIT:
php -n -dzend_extension=opcache.so \
-dpcre.jit=1 -dopcache.jit_buffer_size=64M -dopcache.jit=tracing -dopcache.enable=1 -dopcache.enable_cli=1 \
tests/bench.php
Example output
Filter: MessagePack\Tests\Perf\Filter\ListFilter
Rounds: 3
Iterations: 100000
=============================================
Test/Target Packer BufferUnpacker
---------------------------------------------
nil .................. 0.0005 ........ 0.0054
false ................ 0.0004 ........ 0.0059
true ................. 0.0004 ........ 0.0059
7-bit uint #1 ........ 0.0010 ........ 0.0047
7-bit uint #2 ........ 0.0010 ........ 0.0046
7-bit uint #3 ........ 0.0010 ........ 0.0046
5-bit sint #1 ........ 0.0025 ........ 0.0046
5-bit sint #2 ........ 0.0023 ........ 0.0046
5-bit sint #3 ........ 0.0024 ........ 0.0045
8-bit uint #1 ........ 0.0043 ........ 0.0081
8-bit uint #2 ........ 0.0043 ........ 0.0079
8-bit uint #3 ........ 0.0041 ........ 0.0080
16-bit uint #1 ....... 0.0064 ........ 0.0095
16-bit uint #2 ....... 0.0064 ........ 0.0091
16-bit uint #3 ....... 0.0064 ........ 0.0094
32-bit uint #1 ....... 0.0085 ........ 0.0114
32-bit uint #2 ....... 0.0077 ........ 0.0122
32-bit uint #3 ....... 0.0077 ........ 0.0120
64-bit uint #1 ....... 0.0085 ........ 0.0159
64-bit uint #2 ....... 0.0086 ........ 0.0157
64-bit uint #3 ....... 0.0086 ........ 0.0158
8-bit int #1 ......... 0.0042 ........ 0.0080
8-bit int #2 ......... 0.0042 ........ 0.0080
8-bit int #3 ......... 0.0042 ........ 0.0081
16-bit int #1 ........ 0.0065 ........ 0.0095
16-bit int #2 ........ 0.0065 ........ 0.0090
16-bit int #3 ........ 0.0056 ........ 0.0085
32-bit int #1 ........ 0.0067 ........ 0.0107
32-bit int #2 ........ 0.0066 ........ 0.0106
32-bit int #3 ........ 0.0063 ........ 0.0104
64-bit int #1 ........ 0.0072 ........ 0.0162
64-bit int #2 ........ 0.0073 ........ 0.0174
64-bit int #3 ........ 0.0072 ........ 0.0164
64-bit int #4 ........ 0.0077 ........ 0.0161
64-bit float #1 ...... 0.0053 ........ 0.0135
64-bit float #2 ...... 0.0053 ........ 0.0135
64-bit float #3 ...... 0.0052 ........ 0.0135
fix string #1 ....... -0.0002 ........ 0.0044
fix string #2 ........ 0.0035 ........ 0.0067
fix string #3 ........ 0.0035 ........ 0.0077
fix string #4 ........ 0.0033 ........ 0.0078
8-bit string #1 ...... 0.0059 ........ 0.0110
8-bit string #2 ...... 0.0063 ........ 0.0121
8-bit string #3 ...... 0.0064 ........ 0.0124
16-bit string #1 ..... 0.0099 ........ 0.0146
16-bit string #2 ..... 0.1522 ........ 0.1474
32-bit string ........ 0.1511 ........ 0.1483
wide char string #1 .. 0.0039 ........ 0.0084
wide char string #2 .. 0.0073 ........ 0.0123
8-bit binary #1 ...... 0.0040 ........ 0.0112
8-bit binary #2 ...... 0.0075 ........ 0.0123
8-bit binary #3 ...... 0.0077 ........ 0.0129
16-bit binary ........ 0.0096 ........ 0.0145
32-bit binary ........ 0.1535 ........ 0.1479
fix array #1 ......... 0.0008 ........ 0.0061
fix array #2 ......... 0.0121 ........ 0.0165
fix array #3 ......... 0.0193 ........ 0.0222
16-bit array #1 ...... 0.0607 ........ 0.0479
16-bit array #2 ........... S ............. S
32-bit array .............. S ............. S
complex array ........ 0.0749 ........ 0.0824
fix map #1 ........... 0.0329 ........ 0.0431
fix map #2 ........... 0.0161 ........ 0.0189
fix map #3 ........... 0.0205 ........ 0.0262
fix map #4 ........... 0.0252 ........ 0.0205
16-bit map #1 ........ 0.1016 ........ 0.0927
16-bit map #2 ............. S ............. S
32-bit map ................ S ............. S
complex map .......... 0.1096 ........ 0.1030
fixext 1 ............. 0.0157 ........ 0.0161
fixext 2 ............. 0.0175 ........ 0.0183
fixext 4 ............. 0.0156 ........ 0.0185
fixext 8 ............. 0.0163 ........ 0.0184
fixext 16 ............ 0.0164 ........ 0.0182
8-bit ext ............ 0.0158 ........ 0.0207
16-bit ext ........... 0.0203 ........ 0.0219
32-bit ext ........... 0.1614 ........ 0.1539
32-bit timestamp #1 .. 0.0195 ........ 0.0249
32-bit timestamp #2 .. 0.0188 ........ 0.0260
64-bit timestamp #1 .. 0.0207 ........ 0.0281
64-bit timestamp #2 .. 0.0212 ........ 0.0291
64-bit timestamp #3 .. 0.0207 ........ 0.0295
96-bit timestamp #1 .. 0.0222 ........ 0.0358
96-bit timestamp #2 .. 0.0228 ........ 0.0353
96-bit timestamp #3 .. 0.0210 ........ 0.0319
=============================================
Total 1.6432 1.9674
Skipped 4 4
Failed 0 0
Ignored 0 0
You may change default benchmark settings by defining the following environment variables:
| Name | Default |
|---|---|
| MP_BENCH_TARGETS | pure_p,pure_u, see a list of available targets |
| MP_BENCH_ITERATIONS | 100_000 |
| MP_BENCH_DURATION | not set |
| MP_BENCH_ROUNDS | 3 |
| MP_BENCH_TESTS | -@slow, see a list of available tests |
For example:
export MP_BENCH_TARGETS=pure_p
export MP_BENCH_ITERATIONS=1000000
export MP_BENCH_ROUNDS=5
# a comma separated list of test names
export MP_BENCH_TESTS='complex array, complex map'
# or a group name
# export MP_BENCH_TESTS='-@slow' // @pecl_comp
# or a regexp
# export MP_BENCH_TESTS='/complex (array|map)/'
Another example, benchmarking both the library and the PECL extension:
MP_BENCH_TARGETS=pure_p,pure_u,pecl_p,pecl_u \
php -n -dextension=msgpack.so -dzend_extension=opcache.so \
-dpcre.jit=1 -dopcache.enable=1 -dopcache.enable_cli=1 \
tests/bench.php
Example output
Filter: MessagePack\Tests\Perf\Filter\ListFilter
Rounds: 3
Iterations: 100000
===========================================================================
Test/Target Packer BufferUnpacker msgpack_pack msgpack_unpack
---------------------------------------------------------------------------
nil .................. 0.0031 ........ 0.0141 ...... 0.0055 ........ 0.0064
false ................ 0.0039 ........ 0.0154 ...... 0.0056 ........ 0.0053
true ................. 0.0038 ........ 0.0139 ...... 0.0056 ........ 0.0044
7-bit uint #1 ........ 0.0061 ........ 0.0110 ...... 0.0059 ........ 0.0046
7-bit uint #2 ........ 0.0065 ........ 0.0119 ...... 0.0042 ........ 0.0029
7-bit uint #3 ........ 0.0054 ........ 0.0117 ...... 0.0045 ........ 0.0025
5-bit sint #1 ........ 0.0047 ........ 0.0103 ...... 0.0038 ........ 0.0022
5-bit sint #2 ........ 0.0048 ........ 0.0117 ...... 0.0038 ........ 0.0022
5-bit sint #3 ........ 0.0046 ........ 0.0102 ...... 0.0038 ........ 0.0023
8-bit uint #1 ........ 0.0063 ........ 0.0174 ...... 0.0039 ........ 0.0031
8-bit uint #2 ........ 0.0063 ........ 0.0167 ...... 0.0040 ........ 0.0029
8-bit uint #3 ........ 0.0063 ........ 0.0168 ...... 0.0039 ........ 0.0030
16-bit uint #1 ....... 0.0092 ........ 0.0222 ...... 0.0049 ........ 0.0030
16-bit uint #2 ....... 0.0096 ........ 0.0227 ...... 0.0042 ........ 0.0046
16-bit uint #3 ....... 0.0123 ........ 0.0274 ...... 0.0059 ........ 0.0051
32-bit uint #1 ....... 0.0136 ........ 0.0331 ...... 0.0060 ........ 0.0048
32-bit uint #2 ....... 0.0130 ........ 0.0336 ...... 0.0070 ........ 0.0048
32-bit uint #3 ....... 0.0127 ........ 0.0329 ...... 0.0051 ........ 0.0048
64-bit uint #1 ....... 0.0126 ........ 0.0268 ...... 0.0055 ........ 0.0049
64-bit uint #2 ....... 0.0135 ........ 0.0281 ...... 0.0052 ........ 0.0046
64-bit uint #3 ....... 0.0131 ........ 0.0274 ...... 0.0069 ........ 0.0044
8-bit int #1 ......... 0.0077 ........ 0.0236 ...... 0.0058 ........ 0.0044
8-bit int #2 ......... 0.0087 ........ 0.0244 ...... 0.0058 ........ 0.0048
8-bit int #3 ......... 0.0084 ........ 0.0241 ...... 0.0055 ........ 0.0049
16-bit int #1 ........ 0.0112 ........ 0.0271 ...... 0.0048 ........ 0.0045
16-bit int #2 ........ 0.0124 ........ 0.0292 ...... 0.0057 ........ 0.0049
16-bit int #3 ........ 0.0118 ........ 0.0270 ...... 0.0058 ........ 0.0050
32-bit int #1 ........ 0.0137 ........ 0.0366 ...... 0.0058 ........ 0.0051
32-bit int #2 ........ 0.0133 ........ 0.0366 ...... 0.0056 ........ 0.0049
32-bit int #3 ........ 0.0129 ........ 0.0350 ...... 0.0052 ........ 0.0048
64-bit int #1 ........ 0.0145 ........ 0.0254 ...... 0.0034 ........ 0.0025
64-bit int #2 ........ 0.0097 ........ 0.0214 ...... 0.0034 ........ 0.0025
64-bit int #3 ........ 0.0096 ........ 0.0287 ...... 0.0059 ........ 0.0050
64-bit int #4 ........ 0.0143 ........ 0.0277 ...... 0.0059 ........ 0.0046
64-bit float #1 ...... 0.0134 ........ 0.0281 ...... 0.0057 ........ 0.0052
64-bit float #2 ...... 0.0141 ........ 0.0281 ...... 0.0057 ........ 0.0050
64-bit float #3 ...... 0.0144 ........ 0.0282 ...... 0.0057 ........ 0.0050
fix string #1 ........ 0.0036 ........ 0.0143 ...... 0.0066 ........ 0.0053
fix string #2 ........ 0.0107 ........ 0.0222 ...... 0.0065 ........ 0.0068
fix string #3 ........ 0.0116 ........ 0.0245 ...... 0.0063 ........ 0.0069
fix string #4 ........ 0.0105 ........ 0.0253 ...... 0.0083 ........ 0.0077
8-bit string #1 ...... 0.0126 ........ 0.0318 ...... 0.0075 ........ 0.0088
8-bit string #2 ...... 0.0121 ........ 0.0295 ...... 0.0076 ........ 0.0086
8-bit string #3 ...... 0.0125 ........ 0.0293 ...... 0.0130 ........ 0.0093
16-bit string #1 ..... 0.0159 ........ 0.0368 ...... 0.0117 ........ 0.0086
16-bit string #2 ..... 0.1547 ........ 0.1686 ...... 0.1516 ........ 0.1373
32-bit string ........ 0.1558 ........ 0.1729 ...... 0.1511 ........ 0.1396
wide char string #1 .. 0.0098 ........ 0.0237 ...... 0.0066 ........ 0.0065
wide char string #2 .. 0.0128 ........ 0.0291 ...... 0.0061 ........ 0.0082
8-bit binary #1 ........... I ............. I ........... F ............. I
8-bit binary #2 ........... I ............. I ........... F ............. I
8-bit binary #3 ........... I ............. I ........... F ............. I
16-bit binary ............. I ............. I ........... F ............. I
32-bit binary ............. I ............. I ........... F ............. I
fix array #1 ......... 0.0040 ........ 0.0129 ...... 0.0120 ........ 0.0058
fix array #2 ......... 0.0279 ........ 0.0390 ...... 0.0143 ........ 0.0165
fix array #3 ......... 0.0415 ........ 0.0463 ...... 0.0162 ........ 0.0187
16-bit array #1 ...... 0.1349 ........ 0.1628 ...... 0.0334 ........ 0.0341
16-bit array #2 ........... S ............. S ........... S ............. S
32-bit array .............. S ............. S ........... S ............. S
complex array ............. I ............. I ........... F ............. F
fix map #1 ................ I ............. I ........... F ............. I
fix map #2 ........... 0.0345 ........ 0.0391 ...... 0.0143 ........ 0.0168
fix map #3 ................ I ............. I ........... F ............. I
fix map #4 ........... 0.0459 ........ 0.0473 ...... 0.0151 ........ 0.0163
16-bit map #1 ........ 0.2518 ........ 0.2962 ...... 0.0400 ........ 0.0490
16-bit map #2 ............. S ............. S ........... S ............. S
32-bit map ................ S ............. S ........... S ............. S
complex map .......... 0.2380 ........ 0.2682 ...... 0.0545 ........ 0.0579
fixext 1 .................. I ............. I ........... F ............. F
fixext 2 .................. I ............. I ........... F ............. F
fixext 4 .................. I ............. I ........... F ............. F
fixext 8 .................. I ............. I ........... F ............. F
fixext 16 ................. I ............. I ........... F ............. F
8-bit ext ................. I ............. I ........... F ............. F
16-bit ext ................ I ............. I ........... F ............. F
32-bit ext ................ I ............. I ........... F ............. F
32-bit timestamp #1 ....... I ............. I ........... F ............. F
32-bit timestamp #2 ....... I ............. I ........... F ............. F
64-bit timestamp #1 ....... I ............. I ........... F ............. F
64-bit timestamp #2 ....... I ............. I ........... F ............. F
64-bit timestamp #3 ....... I ............. I ........... F ............. F
96-bit timestamp #1 ....... I ............. I ........... F ............. F
96-bit timestamp #2 ....... I ............. I ........... F ............. F
96-bit timestamp #3 ....... I ............. I ........... F ............. F
===========================================================================
Total 1.5625 2.3866 0.7735 0.7243
Skipped 4 4 4 4
Failed 0 0 24 17
Ignored 24 24 0 7
With JIT:
MP_BENCH_TARGETS=pure_p,pure_u,pecl_p,pecl_u \
php -n -dextension=msgpack.so -dzend_extension=opcache.so \
-dpcre.jit=1 -dopcache.jit_buffer_size=64M -dopcache.jit=tracing -dopcache.enable=1 -dopcache.enable_cli=1 \
tests/bench.php
Example output
Filter: MessagePack\Tests\Perf\Filter\ListFilter
Rounds: 3
Iterations: 100000
===========================================================================
Test/Target Packer BufferUnpacker msgpack_pack msgpack_unpack
---------------------------------------------------------------------------
nil .................. 0.0001 ........ 0.0052 ...... 0.0053 ........ 0.0042
false ................ 0.0007 ........ 0.0060 ...... 0.0057 ........ 0.0043
true ................. 0.0008 ........ 0.0060 ...... 0.0056 ........ 0.0041
7-bit uint #1 ........ 0.0031 ........ 0.0046 ...... 0.0062 ........ 0.0041
7-bit uint #2 ........ 0.0021 ........ 0.0043 ...... 0.0062 ........ 0.0041
7-bit uint #3 ........ 0.0022 ........ 0.0044 ...... 0.0061 ........ 0.0040
5-bit sint #1 ........ 0.0030 ........ 0.0048 ...... 0.0062 ........ 0.0040
5-bit sint #2 ........ 0.0032 ........ 0.0046 ...... 0.0062 ........ 0.0040
5-bit sint #3 ........ 0.0031 ........ 0.0046 ...... 0.0062 ........ 0.0040
8-bit uint #1 ........ 0.0054 ........ 0.0079 ...... 0.0062 ........ 0.0050
8-bit uint #2 ........ 0.0051 ........ 0.0079 ...... 0.0064 ........ 0.0044
8-bit uint #3 ........ 0.0051 ........ 0.0082 ...... 0.0062 ........ 0.0044
16-bit uint #1 ....... 0.0077 ........ 0.0094 ...... 0.0065 ........ 0.0045
16-bit uint #2 ....... 0.0077 ........ 0.0094 ...... 0.0063 ........ 0.0045
16-bit uint #3 ....... 0.0077 ........ 0.0095 ...... 0.0064 ........ 0.0047
32-bit uint #1 ....... 0.0088 ........ 0.0119 ...... 0.0063 ........ 0.0043
32-bit uint #2 ....... 0.0089 ........ 0.0117 ...... 0.0062 ........ 0.0039
32-bit uint #3 ....... 0.0089 ........ 0.0118 ...... 0.0063 ........ 0.0044
64-bit uint #1 ....... 0.0097 ........ 0.0155 ...... 0.0063 ........ 0.0045
64-bit uint #2 ....... 0.0095 ........ 0.0153 ...... 0.0061 ........ 0.0045
64-bit uint #3 ....... 0.0096 ........ 0.0156 ...... 0.0063 ........ 0.0047
8-bit int #1 ......... 0.0053 ........ 0.0083 ...... 0.0062 ........ 0.0044
8-bit int #2 ......... 0.0052 ........ 0.0080 ...... 0.0062 ........ 0.0044
8-bit int #3 ......... 0.0052 ........ 0.0080 ...... 0.0062 ........ 0.0043
16-bit int #1 ........ 0.0089 ........ 0.0097 ...... 0.0069 ........ 0.0046
16-bit int #2 ........ 0.0075 ........ 0.0093 ...... 0.0063 ........ 0.0043
16-bit int #3 ........ 0.0075 ........ 0.0094 ...... 0.0062 ........ 0.0046
32-bit int #1 ........ 0.0086 ........ 0.0122 ...... 0.0063 ........ 0.0044
32-bit int #2 ........ 0.0087 ........ 0.0120 ...... 0.0066 ........ 0.0046
32-bit int #3 ........ 0.0086 ........ 0.0121 ...... 0.0060 ........ 0.0044
64-bit int #1 ........ 0.0096 ........ 0.0149 ...... 0.0060 ........ 0.0045
64-bit int #2 ........ 0.0096 ........ 0.0157 ...... 0.0062 ........ 0.0044
64-bit int #3 ........ 0.0096 ........ 0.0160 ...... 0.0063 ........ 0.0046
64-bit int #4 ........ 0.0097 ........ 0.0157 ...... 0.0061 ........ 0.0044
64-bit float #1 ...... 0.0079 ........ 0.0153 ...... 0.0056 ........ 0.0044
64-bit float #2 ...... 0.0079 ........ 0.0152 ...... 0.0057 ........ 0.0045
64-bit float #3 ...... 0.0079 ........ 0.0155 ...... 0.0057 ........ 0.0044
fix string #1 ........ 0.0010 ........ 0.0045 ...... 0.0071 ........ 0.0044
fix string #2 ........ 0.0048 ........ 0.0075 ...... 0.0070 ........ 0.0060
fix string #3 ........ 0.0048 ........ 0.0086 ...... 0.0068 ........ 0.0060
fix string #4 ........ 0.0050 ........ 0.0088 ...... 0.0070 ........ 0.0059
8-bit string #1 ...... 0.0081 ........ 0.0129 ...... 0.0069 ........ 0.0062
8-bit string #2 ...... 0.0086 ........ 0.0128 ...... 0.0069 ........ 0.0065
8-bit string #3 ...... 0.0086 ........ 0.0126 ...... 0.0115 ........ 0.0065
16-bit string #1 ..... 0.0105 ........ 0.0137 ...... 0.0128 ........ 0.0068
16-bit string #2 ..... 0.1510 ........ 0.1486 ...... 0.1526 ........ 0.1391
32-bit string ........ 0.1517 ........ 0.1475 ...... 0.1504 ........ 0.1370
wide char string #1 .. 0.0044 ........ 0.0085 ...... 0.0067 ........ 0.0057
wide char string #2 .. 0.0081 ........ 0.0125 ...... 0.0069 ........ 0.0063
8-bit binary #1 ........... I ............. I ........... F ............. I
8-bit binary #2 ........... I ............. I ........... F ............. I
8-bit binary #3 ........... I ............. I ........... F ............. I
16-bit binary ............. I ............. I ........... F ............. I
32-bit binary ............. I ............. I ........... F ............. I
fix array #1 ......... 0.0014 ........ 0.0059 ...... 0.0132 ........ 0.0055
fix array #2 ......... 0.0146 ........ 0.0156 ...... 0.0155 ........ 0.0148
fix array #3 ......... 0.0211 ........ 0.0229 ...... 0.0179 ........ 0.0180
16-bit array #1 ...... 0.0673 ........ 0.0498 ...... 0.0343 ........ 0.0388
16-bit array #2 ........... S ............. S ........... S ............. S
32-bit array .............. S ............. S ........... S ............. S
complex array ............. I ............. I ........... F ............. F
fix map #1 ................ I ............. I ........... F ............. I
fix map #2 ........... 0.0148 ........ 0.0180 ...... 0.0156 ........ 0.0179
fix map #3 ................ I ............. I ........... F ............. I
fix map #4 ........... 0.0252 ........ 0.0201 ...... 0.0214 ........ 0.0167
16-bit map #1 ........ 0.1027 ........ 0.0836 ...... 0.0388 ........ 0.0510
16-bit map #2 ............. S ............. S ........... S ............. S
32-bit map ................ S ............. S ........... S ............. S
complex map .......... 0.1104 ........ 0.1010 ...... 0.0556 ........ 0.0602
fixext 1 .................. I ............. I ........... F ............. F
fixext 2 .................. I ............. I ........... F ............. F
fixext 4 .................. I ............. I ........... F ............. F
fixext 8 .................. I ............. I ........... F ............. F
fixext 16 ................. I ............. I ........... F ............. F
8-bit ext ................. I ............. I ........... F ............. F
16-bit ext ................ I ............. I ........... F ............. F
32-bit ext ................ I ............. I ........... F ............. F
32-bit timestamp #1 ....... I ............. I ........... F ............. F
32-bit timestamp #2 ....... I ............. I ........... F ............. F
64-bit timestamp #1 ....... I ............. I ........... F ............. F
64-bit timestamp #2 ....... I ............. I ........... F ............. F
64-bit timestamp #3 ....... I ............. I ........... F ............. F
96-bit timestamp #1 ....... I ............. I ........... F ............. F
96-bit timestamp #2 ....... I ............. I ........... F ............. F
96-bit timestamp #3 ....... I ............. I ........... F ............. F
===========================================================================
Total 0.9642 1.0909 0.8224 0.7213
Skipped 4 4 4 4
Failed 0 0 24 17
Ignored 24 24 0 7
Note that the msgpack extension (v2.1.2) doesn't support ext, bin and UTF-8 str types.
License
The library is released under the MIT License. See the bundled LICENSE file for details.
Author: rybakit
Source Code: https://github.com/rybakit/msgpack.php
License: MIT License
1648641360
Treebender: A Symbolic Natural Language Parsing Library for Rust
Treebender
A symbolic natural language parsing library for Rust, inspired by HDPSG.
What is this?
This is a library for parsing natural or constructed languages into syntax trees and feature structures. There's no machine learning or probabilistic models, everything is hand-crafted and deterministic.
You can find out more about the motivations of this project in this blog post.
But what are you using it for?
I'm using this to parse a constructed language for my upcoming xenolinguistics game, Themengi.
Motivation
Using a simple 80-line grammar, introduced in the tutorial below, we can parse a simple subset of English, checking reflexive pronoun binding, case, and number agreement.
$ cargo run --bin cli examples/reflexives.fgr
> she likes himself
Parsed 0 trees
> her likes herself
Parsed 0 trees
> she like herself
Parsed 0 trees
> she likes herself
Parsed 1 tree
(0..3: S
(0..1: N (0..1: she))
(1..2: TV (1..2: likes))
(2..3: N (2..3: herself)))
[
child-2: [
case: acc
pron: ref
needs_pron: #0 she
num: sg
child-0: [ word: herself ]
]
child-1: [
tense: nonpast
child-0: [ word: likes ]
num: #1 sg
]
child-0: [
child-0: [ word: she ]
case: nom
pron: #0
num: #1
]
]
Low resource language? Low problem! No need to train on gigabytes of text, just write a grammar using your brain. Let's hypothesize that in American Sign Language, topicalized nouns (expressed with raised eyebrows) must appear first in the sentence. We can write a small grammar (18 lines), and plug in some sentences:
$ cargo run --bin cli examples/asl-wordorder.fgr -n
> boy sit
Parsed 1 tree
(0..2: S
(0..1: NP ((0..1: N (0..1: boy))))
(1..2: IV (1..2: sit)))
> boy throw ball
Parsed 1 tree
(0..3: S
(0..1: NP ((0..1: N (0..1: boy))))
(1..2: TV (1..2: throw))
(2..3: NP ((2..3: N (2..3: ball)))))
> ball nm-raised-eyebrows boy throw
Parsed 1 tree
(0..4: S
(0..2: NP
(0..1: N (0..1: ball))
(1..2: Topic (1..2: nm-raised-eyebrows)))
(2..3: NP ((2..3: N (2..3: boy))))
(3..4: TV (3..4: throw)))
> boy throw ball nm-raised-eyebrows
Parsed 0 trees
Tutorial
As an example, let's say we want to build a parser for English reflexive pronouns (himself, herself, themselves, themself, itself). We'll also support number ("He likes X" v.s. "They like X") and simple embedded clauses ("He said that they like X").
Grammar files are written in a custom language, similar to BNF, called Feature GRammar (.fgr). There's a VSCode syntax highlighting extension for these files available as fgr-syntax.
We'll start by defining our lexicon. The lexicon is the set of terminal symbols (symbols in the actual input) that the grammar will match. Terminal symbols must start with a lowercase letter, and non-terminal symbols must start with an uppercase letter.
// pronouns
N -> he
N -> him
N -> himself
N -> she
N -> her
N -> herself
N -> they
N -> them
N -> themselves
N -> themself
// names, lowercase as they are terminals
N -> mary
N -> sue
N -> takeshi
N -> robert
// complementizer
Comp -> that
// verbs -- intransitive, transitive, and clausal
IV -> falls
IV -> fall
IV -> fell
TV -> likes
TV -> like
TV -> liked
CV -> says
CV -> say
CV -> said
Next, we can add our sentence rules (they must be added at the top, as the first rule in the file is assumed to be the top-level rule):
// sentence rules
S -> N IV
S -> N TV N
S -> N CV Comp S
// ... previous lexicon ...
Assuming this file is saved as examples/no-features.fgr (which it is :wink:), we can test this file with the built-in CLI:
$ cargo run --bin cli examples/no-features.fgr
> he falls
Parsed 1 tree
(0..2: S
(0..1: N (0..1: he))
(1..2: IV (1..2: falls)))
[
child-1: [ child-0: [ word: falls ] ]
child-0: [ child-0: [ word: he ] ]
]
> he falls her
Parsed 0 trees
> he likes her
Parsed 1 tree
(0..3: S
(0..1: N (0..1: he))
(1..2: TV (1..2: likes))
(2..3: N (2..3: her)))
[
child-2: [ child-0: [ word: her ] ]
child-1: [ child-0: [ word: likes ] ]
child-0: [ child-0: [ word: he ] ]
]
> he likes
Parsed 0 trees
> he said that he likes her
Parsed 1 tree
(0..6: S
(0..1: N (0..1: he))
(1..2: CV (1..2: said))
(2..3: Comp (2..3: that))
(3..6: S
(3..4: N (3..4: he))
(4..5: TV (4..5: likes))
(5..6: N (5..6: her))))
[
child-0: [ child-0: [ word: he ] ]
child-2: [ child-0: [ word: that ] ]
child-1: [ child-0: [ word: said ] ]
child-3: [
child-2: [ child-0: [ word: her ] ]
child-1: [ child-0: [ word: likes ] ]
child-0: [ child-0: [ word: he ] ]
]
]
> he said that he
Parsed 0 trees
This grammar already parses some correct sentences, and blocks some trivially incorrect ones. However, it doesn't care about number, case, or reflexives right now:
> she likes himself // unbound reflexive pronoun
Parsed 1 tree
(0..3: S
(0..1: N (0..1: she))
(1..2: TV (1..2: likes))
(2..3: N (2..3: himself)))
[
child-0: [ child-0: [ word: she ] ]
child-2: [ child-0: [ word: himself ] ]
child-1: [ child-0: [ word: likes ] ]
]
> him like her // incorrect case on the subject pronoun, should be nominative
// (he) instead of accusative (him)
Parsed 1 tree
(0..3: S
(0..1: N (0..1: him))
(1..2: TV (1..2: like))
(2..3: N (2..3: her)))
[
child-0: [ child-0: [ word: him ] ]
child-1: [ child-0: [ word: like ] ]
child-2: [ child-0: [ word: her ] ]
]
> he like her // incorrect verb number agreement
Parsed 1 tree
(0..3: S
(0..1: N (0..1: he))
(1..2: TV (1..2: like))
(2..3: N (2..3: her)))
[
child-2: [ child-0: [ word: her ] ]
child-1: [ child-0: [ word: like ] ]
child-0: [ child-0: [ word: he ] ]
]
To fix this, we need to add features to our lexicon, and restrict the sentence rules based on features.
Features are added with square brackets, and are key: value pairs separated by commas. **top** is a special feature value, which basically means "unspecified" -- we'll come back to it later. Features that are unspecified are also assumed to have a **top** value, but sometimes explicitly stating top is more clear.
/// Pronouns
// The added features are:
// * num: sg or pl, whether this noun wants a singular verb (likes) or
// a plural verb (like). note this is grammatical number, so for example
// singular they takes plural agreement ("they like X", not *"they likes X")
// * case: nom or acc, whether this noun is nominative or accusative case.
// nominative case goes in the subject, and accusative in the object.
// e.g., "he fell" and "she likes him", not *"him fell" and *"her likes he"
// * pron: he, she, they, or ref -- what type of pronoun this is
// * needs_pron: whether this is a reflexive that needs to bind to another
// pronoun.
N[ num: sg, case: nom, pron: he ] -> he
N[ num: sg, case: acc, pron: he ] -> him
N[ num: sg, case: acc, pron: ref, needs_pron: he ] -> himself
N[ num: sg, case: nom, pron: she ] -> she
N[ num: sg, case: acc, pron: she ] -> her
N[ num: sg, case: acc, pron: ref, needs_pron: she] -> herself
N[ num: pl, case: nom, pron: they ] -> they
N[ num: pl, case: acc, pron: they ] -> them
N[ num: pl, case: acc, pron: ref, needs_pron: they ] -> themselves
N[ num: sg, case: acc, pron: ref, needs_pron: they ] -> themself
// Names
// The added features are:
// * num: sg, as people are singular ("mary likes her" / *"mary like her")
// * case: **top**, as names can be both subjects and objects
// ("mary likes her" / "she likes mary")
// * pron: whichever pronoun the person uses for reflexive agreement
// mary pron: she => mary likes herself
// sue pron: they => sue likes themself
// takeshi pron: he => takeshi likes himself
N[ num: sg, case: **top**, pron: she ] -> mary
N[ num: sg, case: **top**, pron: they ] -> sue
N[ num: sg, case: **top**, pron: he ] -> takeshi
N[ num: sg, case: **top**, pron: he ] -> robert
// Complementizer doesn't need features
Comp -> that
// Verbs -- intransitive, transitive, and clausal
// The added features are:
// * num: sg, pl, or **top** -- to match the noun numbers.
// **top** will match either sg or pl, as past-tense verbs in English
// don't agree in number: "he fell" and "they fell" are both fine
// * tense: past or nonpast -- this won't be used for agreement, but will be
// copied into the final feature structure, and the client code could do
// something with it
IV[ num: sg, tense: nonpast ] -> falls
IV[ num: pl, tense: nonpast ] -> fall
IV[ num: **top**, tense: past ] -> fell
TV[ num: sg, tense: nonpast ] -> likes
TV[ num: pl, tense: nonpast ] -> like
TV[ num: **top**, tense: past ] -> liked
CV[ num: sg, tense: nonpast ] -> says
CV[ num: pl, tense: nonpast ] -> say
CV[ num: **top**, tense: past ] -> said
Now that our lexicon is updated with features, we can update our sentence rules to constrain parsing based on those features. This uses two new features, tags and unification. Tags allow features to be associated between nodes in a rule, and unification controls how those features are compatible. The rules for unification are:
- A string feature can unify with a string feature with the same value
- A top feature can unify with anything, and the nodes are merged
- A complex feature ([ ... ] structure) is recursively unified with another complex feature.
If unification fails anywhere, the parse is aborted and the tree is discarded. This allows the programmer to discard trees if features don't match.
// Sentence rules
// Intransitive verb:
// * Subject must be nominative case
// * Subject and verb must agree in number (copied through #1)
S -> N[ case: nom, num: #1 ] IV[ num: #1 ]
// Transitive verb:
// * Subject must be nominative case
// * Subject and verb must agree in number (copied through #2)
// * If there's a reflexive in the object position, make sure its `needs_pron`
// feature matches the subject's `pron` feature. If the object isn't a
// reflexive, then its `needs_pron` feature will implicitly be `**top**`, so
// will unify with anything.
S -> N[ case: nom, pron: #1, num: #2 ] TV[ num: #2 ] N[ case: acc, needs_pron: #1 ]
// Clausal verb:
// * Subject must be nominative case
// * Subject and verb must agree in number (copied through #1)
// * Reflexives can't cross clause boundaries (*"He said that she likes himself"),
// so we can ignore reflexives and delegate to inner clause rule
S -> N[ case: nom, num: #1 ] CV[ num: #1 ] Comp S
Now that we have this augmented grammar (available as examples/reflexives.fgr), we can try it out and see that it rejects illicit sentences that were previously accepted, while still accepting valid ones:
> he fell
Parsed 1 tree
(0..2: S
(0..1: N (0..1: he))
(1..2: IV (1..2: fell)))
[
child-1: [
child-0: [ word: fell ]
num: #0 sg
tense: past
]
child-0: [
pron: he
case: nom
num: #0
child-0: [ word: he ]
]
]
> he like him
Parsed 0 trees
> he likes himself
Parsed 1 tree
(0..3: S
(0..1: N (0..1: he))
(1..2: TV (1..2: likes))
(2..3: N (2..3: himself)))
[
child-1: [
num: #0 sg
child-0: [ word: likes ]
tense: nonpast
]
child-2: [
needs_pron: #1 he
num: sg
child-0: [ word: himself ]
pron: ref
case: acc
]
child-0: [
child-0: [ word: he ]
pron: #1
num: #0
case: nom
]
]
> he likes herself
Parsed 0 trees
> mary likes herself
Parsed 1 tree
(0..3: S
(0..1: N (0..1: mary))
(1..2: TV (1..2: likes))
(2..3: N (2..3: herself)))
[
child-0: [
pron: #0 she
num: #1 sg
case: nom
child-0: [ word: mary ]
]
child-1: [
tense: nonpast
child-0: [ word: likes ]
num: #1
]
child-2: [
child-0: [ word: herself ]
num: sg
pron: ref
case: acc
needs_pron: #0
]
]
> mary likes themself
Parsed 0 trees
> sue likes themself
Parsed 1 tree
(0..3: S
(0..1: N (0..1: sue))
(1..2: TV (1..2: likes))
(2..3: N (2..3: themself)))
[
child-0: [
pron: #0 they
child-0: [ word: sue ]
case: nom
num: #1 sg
]
child-1: [
tense: nonpast
num: #1
child-0: [ word: likes ]
]
child-2: [
needs_pron: #0
case: acc
pron: ref
child-0: [ word: themself ]
num: sg
]
]
> sue likes himself
Parsed 0 trees
If this is interesting to you and you want to learn more, you can check out my blog series, the excellent textbook Syntactic Theory: A Formal Introduction (2nd ed.), and the DELPH-IN project, whose work on the LKB inspired this simplified version.
Using from code
I need to write this section in more detail, but if you're comfortable with Rust, I suggest looking through the codebase. It's not perfect, it started as one of my first Rust projects (after migrating through F# -> TypeScript -> C in search of the right performance/ergonomics tradeoff), and it could use more tests, but overall it's not too bad.
Basically, the processing pipeline is:
- Make a
Grammarstruct
Grammaris defined inrules.rs.- The easiest way to make a
GrammarisGrammar::parse_from_file, which is mostly a hand-written recusive descent parser inparse_grammar.rs. Yes, I recognize the irony here.
- It takes input (in
Grammar::parse, which does everything for you, orGrammar::parse_chart, which just does the chart) - The input is first chart-parsed in
earley.rs - Then, a forest is built from the chart, in
forest.rs, using an algorithm I found in a very useful blog series I forget the URL for, because the algorithms in the academic literature for this are... weird. - Finally, the feature unification is used to prune the forest down to only valid trees. It would be more efficient to do this during parsing, but meh.
The most interesting thing you can do via code and not via the CLI is probably getting at the raw feature DAG, as that would let you do things like pronoun coreference. The DAG code is in featurestructure.rs, and should be fairly approachable -- there's a lot of Rust ceremony around Rc<RefCell<...>> because using an arena allocation crate seemed too harlike overkill, but that is somewhat mitigated by the NodeRef type alias. Hit me up at https://vgel.me/contact if you need help with anything here!
Download Details:
Author: vgel
Source Code: https://github.com/vgel/treebender
License: MIT License
1667488080
Py Rouge: A Full Python Implementation Of The ROUGE Metric
Py-rouge
A full Python implementation of the ROUGE metric, producing same results as in the official perl implementation.
Important remarks
- The original Porter stemmer in NLTK is slightly different than the one use in the official ROUGE perl script as it has been written by end. Therefore, there might be slightly different stems for certain words. For DUC2004 dataset, I have identified these words and this script produces same stems.
- The official ROUGE perl script use resampling strategy to compute the average with confidence intervals. Therefore, we might have a difference
<3e-5for ROUGE-L as well as ROUGE-W and<4e-5for ROUGE-N. - Finally, ROUGE-1.5.5. has a bug: should have $tmpTextLen += $sLen at line 2101. Here, the last sentence, $limitBytes is taken instead of $limitBytes-$tmpTextLen (as $tmpTextLen is never updated with bytes length limit). It has been fixed in this code. This bug does not have a consequence for the default evaluation
-b 665.
In case of doubts, please see all the implemented tests to compare outputs between the official ROUGE-1.5.5 and this script.
Installation
Package is uploaded on PyPI <https://pypi.org/project/py-rouge>_.
You can install it with pip:
pip install py-rouge
or do it manually:
git clone https://github.com/Diego999/py-rouge
cd py-rouge
python setup.py install
Issues/Pull Requests/Feedbacks
Don't hesitate to contact for any feedback or create issues/pull requests (especially if you want to rewrite the stemmer implemented in ROUGE-1.5.5 in python ;)).
Example
import rouge
def prepare_results(m, p, r, f):
return '\t{}:\t{}: {:5.2f}\t{}: {:5.2f}\t{}: {:5.2f}'.format(m, 'P', 100.0 * p, 'R', 100.0 * r, 'F1', 100.0 * f)
for aggregator in ['Avg', 'Best', 'Individual']:
print('Evaluation with {}'.format(aggregator))
apply_avg = aggregator == 'Avg'
apply_best = aggregator == 'Best'
evaluator = rouge.Rouge(metrics=['rouge-n', 'rouge-l', 'rouge-w'],
max_n=4,
limit_length=True,
length_limit=100,
length_limit_type='words',
apply_avg=apply_avg,
apply_best=apply_best,
alpha=0.5, # Default F1_score
weight_factor=1.2,
stemming=True)
hypothesis_1 = "King Norodom Sihanouk has declined requests to chair a summit of Cambodia 's top political leaders , saying the meeting would not bring any progress in deadlocked negotiations to form a government .\nGovernment and opposition parties have asked King Norodom Sihanouk to host a summit meeting after a series of post-election negotiations between the two opposition groups and Hun Sen 's party to form a new government failed .\nHun Sen 's ruling party narrowly won a majority in elections in July , but the opposition _ claiming widespread intimidation and fraud _ has denied Hun Sen the two-thirds vote in parliament required to approve the next government .\n"
references_1 = ["Prospects were dim for resolution of the political crisis in Cambodia in October 1998.\nPrime Minister Hun Sen insisted that talks take place in Cambodia while opposition leaders Ranariddh and Sam Rainsy, fearing arrest at home, wanted them abroad.\nKing Sihanouk declined to chair talks in either place.\nA U.S. House resolution criticized Hun Sen's regime while the opposition tried to cut off his access to loans.\nBut in November the King announced a coalition government with Hun Sen heading the executive and Ranariddh leading the parliament.\nLeft out, Sam Rainsy sought the King's assurance of Hun Sen's promise of safety and freedom for all politicians.",
"Cambodian prime minister Hun Sen rejects demands of 2 opposition parties for talks in Beijing after failing to win a 2/3 majority in recent elections.\nSihanouk refuses to host talks in Beijing.\nOpposition parties ask the Asian Development Bank to stop loans to Hun Sen's government.\nCCP defends Hun Sen to the US Senate.\nFUNCINPEC refuses to share the presidency.\nHun Sen and Ranariddh eventually form a coalition at summit convened by Sihanouk.\nHun Sen remains prime minister, Ranariddh is president of the national assembly, and a new senate will be formed.\nOpposition leader Rainsy left out.\nHe seeks strong assurance of safety should he return to Cambodia.\n",
]
hypothesis_2 = "China 's government said Thursday that two prominent dissidents arrested this week are suspected of endangering national security _ the clearest sign yet Chinese leaders plan to quash a would-be opposition party .\nOne leader of a suppressed new political party will be tried on Dec. 17 on a charge of colluding with foreign enemies of China '' to incite the subversion of state power , '' according to court documents given to his wife on Monday .\nWith attorneys locked up , harassed or plain scared , two prominent dissidents will defend themselves against charges of subversion Thursday in China 's highest-profile dissident trials in two years .\n"
references_2 = "Hurricane Mitch, category 5 hurricane, brought widespread death and destruction to Central American.\nEspecially hard hit was Honduras where an estimated 6,076 people lost their lives.\nThe hurricane, which lingered off the coast of Honduras for 3 days before moving off, flooded large areas, destroying crops and property.\nThe U.S. and European Union were joined by Pope John Paul II in a call for money and workers to help the stricken area.\nPresident Clinton sent Tipper Gore, wife of Vice President Gore to the area to deliver much needed supplies to the area, demonstrating U.S. commitment to the recovery of the region.\n"
all_hypothesis = [hypothesis_1, hypothesis_2]
all_references = [references_1, references_2]
scores = evaluator.get_scores(all_hypothesis, all_references)
for metric, results in sorted(scores.items(), key=lambda x: x[0]):
if not apply_avg and not apply_best: # value is a type of list as we evaluate each summary vs each reference
for hypothesis_id, results_per_ref in enumerate(results):
nb_references = len(results_per_ref['p'])
for reference_id in range(nb_references):
print('\tHypothesis #{} & Reference #{}: '.format(hypothesis_id, reference_id))
print('\t' + prepare_results(metric,results_per_ref['p'][reference_id], results_per_ref['r'][reference_id], results_per_ref['f'][reference_id]))
print()
else:
print(prepare_results(metric, results['p'], results['r'], results['f']))
print()
It produces the following output:
Evaluation with Avg
rouge-1: P: 28.62 R: 26.46 F1: 27.49
rouge-2: P: 4.21 R: 3.92 F1: 4.06
rouge-3: P: 0.80 R: 0.74 F1: 0.77
rouge-4: P: 0.00 R: 0.00 F1: 0.00
rouge-l: P: 30.52 R: 28.57 F1: 29.51
rouge-w: P: 15.85 R: 8.28 F1: 10.87
Evaluation with Best
rouge-1: P: 30.44 R: 28.36 F1: 29.37
rouge-2: P: 4.74 R: 4.46 F1: 4.59
rouge-3: P: 1.06 R: 0.98 F1: 1.02
rouge-4: P: 0.00 R: 0.00 F1: 0.00
rouge-l: P: 31.54 R: 29.71 F1: 30.60
rouge-w: P: 16.42 R: 8.82 F1: 11.47
Evaluation with Individual
Hypothesis #0 & Reference #0:
rouge-1: P: 38.54 R: 35.58 F1: 37.00
Hypothesis #0 & Reference #1:
rouge-1: P: 45.83 R: 43.14 F1: 44.44
Hypothesis #1 & Reference #0:
rouge-1: P: 15.05 R: 13.59 F1: 14.29
Hypothesis #0 & Reference #0:
rouge-2: P: 7.37 R: 6.80 F1: 7.07
Hypothesis #0 & Reference #1:
rouge-2: P: 9.47 R: 8.91 F1: 9.18
Hypothesis #1 & Reference #0:
rouge-2: P: 0.00 R: 0.00 F1: 0.00
Hypothesis #0 & Reference #0:
rouge-3: P: 2.13 R: 1.96 F1: 2.04
Hypothesis #0 & Reference #1:
rouge-3: P: 1.06 R: 1.00 F1: 1.03
Hypothesis #1 & Reference #0:
rouge-3: P: 0.00 R: 0.00 F1: 0.00
Hypothesis #0 & Reference #0:
rouge-4: P: 0.00 R: 0.00 F1: 0.00
Hypothesis #0 & Reference #1:
rouge-4: P: 0.00 R: 0.00 F1: 0.00
Hypothesis #1 & Reference #0:
rouge-4: P: 0.00 R: 0.00 F1: 0.00
Hypothesis #0 & Reference #0:
rouge-l: P: 42.11 R: 39.39 F1: 40.70
Hypothesis #0 & Reference #1:
rouge-l: P: 46.19 R: 43.92 F1: 45.03
Hypothesis #1 & Reference #0:
rouge-l: P: 16.88 R: 15.50 F1: 16.16
Hypothesis #0 & Reference #0:
rouge-w: P: 22.27 R: 11.49 F1: 15.16
Hypothesis #0 & Reference #1:
rouge-w: P: 24.56 R: 13.60 F1: 17.51
Hypothesis #1 & Reference #0:
rouge-w: P: 8.29 R: 4.04 F1: 5.43Download Details:
Author: Diego999
Source Code: https://github.com/Diego999/py-rouge
License: Apache-2.0 license
1656856140
A Plugin for D3.js That Allows You to Easy Use Context-menus
d3-context-menu
This is a plugin for d3.js that allows you to easy use context-menus in your visualizations. It's 100% d3 based and done in the "d3 way", so you don't need to worry about including additional frameworks.
Install with Bower
bower install d3-context-menu
Basic usage:
// Define your menu
var menu = [
{
title: 'Item #1',
action: function(d) {
console.log('Item #1 clicked!');
console.log('The data for this circle is: ' + d);
},
disabled: false // optional, defaults to false
},
{
title: 'Item #2',
action: function(d) {
console.log('You have clicked the second item!');
console.log('The data for this circle is: ' + d);
}
}
]
var data = [1, 2, 3];
var g = d3.select('body').append('svg')
.attr('width', 200)
.attr('height', 400)
.append('g');
g.selectAll('circles')
.data(data)
.enter()
.append('circle')
.attr('r', 30)
.attr('fill', 'steelblue')
.attr('cx', function(d) {
return 100;
})
.attr('cy', function(d) {
return d * 100;
})
.on('contextmenu', d3.contextMenu(menu)); // attach menu to element
});
Advanced usage:
Headers and Dividers
Menus can have Headers and Dividers. To specify a header simply don't define an "action" property. To specify a divider, simply add a "divider: true" property to the menu item, and it'll be considered a divider. Example menu definition:
var menu = [
{
title: 'Header',
},
{
title: 'Normal item',
action: function() {}
},
{
divider: true
},
{
title: 'Last item',
action: function() {}
}
];
Nested Menu
Menus can have Nested Menu. To specify a nested menu, simply add "children" property. Children has item of array.
var menu = [
{
title: 'Parent',
children: [
{
title: 'Child',
children: [
{
// header
title: 'Grand-Child1'
},
{
// normal
title: 'Grand-Child2',
action: function() {}
},
{
// divider
divider: true
},
{
// disable
title: 'Grand-Child3',
action: function() {}
}
]
}
]
},
];
See the index.htm file in the example folder to see this in action.
Pre-show callback
You can pass in a callback that will be executed before the context menu appears. This can be useful if you need something to close tooltips or perform some other task before the menu appears:
...
.on('contextmenu', d3.contextMenu(menu, function() {
console.log('Quick! Before the menu appears!');
})); // attach menu to element
Post-show callback
You can pass in a callback that will be executed after the context menu appears using the onClose option:
...
.on('contextmenu', d3.contextMenu(menu, {
onOpen: function() {
console.log('Quick! Before the menu appears!');
},
onClose: function() {
console.log('Menu has been closed.');
}
})); // attach menu to element
Context-sensitive menu items
You can use information from your context in menu names, simply specify a function for title which returns a string:
var menu = [
{
title: function(d) {
return 'Delete circle '+d.circleName;
},
action: function(d) {
// delete it
}
},
{
title: function(d) {
return 'Item 2';
},
action: function(d) {
// do nothing interesting
}
}
];
// Menu shown is:
[Delete Circle MyCircle]
[Item 2]
Dynamic menu list
You can also have different lists of menu items for different nodes if menu is a function:
var menu = function(data) {
if (data.x > 100) {
return [{
title: 'Item #1',
action: function(d) {
console.log('Item #1 clicked!');
console.log('The data for this circle is: ' + d);
}
}];
} else {
return [{
title: 'Item #1',
action: function(d) {
console.log('Item #1 clicked!');
console.log('The data for this circle is: ' + d);
}
}, {
title: 'Item #2',
action: function(d) {
console.log('Item #2 clicked!');
console.log('The data for this circle is: ' + d);
}
}];
}
};
// Menu shown for nodes with x < 100 contains 1 item, while other nodes have 2 menu items
Deleting Nodes Example
The following example shows how to add a right click menu to a tree diagram:
http://plnkr.co/edit/bDBe0xGX1mCLzqYGOqOS?p=info
Explicitly set menu position
Default position can be overwritten by providing a position option (either object or function returning an object):
...
.on('contextmenu', d3.contextMenu(menu, {
onOpen: function() {
...
},
onClose: function() {
...
},
position: {
top: 100,
left: 200
}
})); // attach menu to element
or
...
.on('contextmenu', d3.contextMenu(menu, {
onOpen: function() {
...
},
onClose: function() {
...
},
position: function(d) {
var elm = this;
var bounds = elm.getBoundingClientRect();
// eg. align bottom-left
return {
top: bounds.top + bounds.height,
left: bounds.left
}
}
})); // attach menu to element
Set your own CSS class as theme (make sure to style it)
d3.contextMenu(menu, {
...
theme: 'my-awesome-theme'
});
or
d3.contextMenu(menu, {
...
theme: function () {
if (foo) {
return 'my-foo-theme';
}
else {
return 'my-awesome-theme';
}
}
});
Close the context menu programatically (can be used as cleanup, as well)
d3.contextMenu('close');
The following example shows how to add a right click menu to a tree diagram:
http://plnkr.co/edit/bDBe0xGX1mCLzqYGOqOS?p=info
Additional callback arguments
Depending on the D3 library version used the callback functions can provide an additional argument:
- for D3 6.x or above it will be the event, since the global d3.event is not available.
var menu = [
{
title: 'Item #1',
action: function(d, event) {
console.log('Item #1 clicked!');
console.log('The data for this circle is: ' + d);
console.log('The event is: ' + event);
}
}
]
- for D3 5.x or below it will be the index, for backward compatibility reasons.
var menu = [
{
title: 'Item #1',
action: function(d, index) {
console.log('Item #1 clicked!');
console.log('The data for this circle is: ' + d);
console.log('The index is: ' + index);
}
}
]
What's new in version 2.1.0
- Added support for accessing event information in with D3 6.x.
What's new in version 2.0.0
- Added support for D3 6.x
- The
indexparameter of callbacks are undefined when using D3 6.x or above. See the index.htm file in the example folder to see how to get the properindexvalue in that case. - Added class property for menu items that allows specifying CSS classes (see: https://github.com/patorjk/d3-context-menu/pull/56).
What's new in version 1.1.2
- Menu updated so it wont go off bottom or right of screen when window is smaller.
What's new in version 1.1.1
- Menu close bug fix.
What's new in version 1.1.0
- Nested submenus are now supported.
What's new in version 1.0.1
- Default theme styles extracted to their own CSS class (
d3-context-menu-theme) - Ability to specify own theme css class via the
themeconfiguration option (as string or function returning string) - onOpen/onClose callbacks now have consistent signature (they receive
dataandindex, andthisargument refers to the DOM element the context menu is related to) - all other functions (eg.
position,menu) have the same signature andthisobject asonClose/onOpen - Context menu now closes on
mousedownoutside of the menu, instead ofclickoutside (to mimic behaviour of the native context menu) disabledanddividercan now be functions as well and have the same signature andthisobject as explained above- Close the context menu programatically using
d3.contextMenu('close');
What's new in version 0.2.1
- Ability to set menu position
- Minified css and js versions
What's new in version 0.1.3
- Fixed issue where context menu element is never removed from DOM
- Fixed issue where
<body>click event is never removed - Fixed issue where the incorrect
onClosecallback was called when menu was closed as a result of clicking outside
What's new in version 0.1.2
- If contextmenu is clicked twice it will close rather than open the browser's context menu.
What's new in version 0.1.1
- Header and Divider items.
- Ability to disable items.
It's written to be very light weight and customizable. You can see it in action here:
http://plnkr.co/edit/hAx36JQhb0RsvVn7TomS?p=info
Author: Patorjk
Source Code: https://github.com/patorjk/d3-context-menu
License: MIT license
1595098800
Top 130 Android Interview Questions - Crack Technical Interview Now!
Android Interview Questions and Answers from Beginner to Advanced level
DataFlair is committed to provide you all the resources to make you an android professional. We started with android tutorials along with practicals, then we published Real-time android projects along with source code. Now, we come up with frequently asked android interview questions, which will help you in showing expertise in your next interview.
Android Interview Questions – Get ready for your next interview
Android – one of the hottest technologies, which is having a bright future. Get ready to crack your next interview with the following android interview questions. These interview questions start with basic and cover deep concepts along with advanced topics.
Android Interview Questions for Freshers
1. What is Android?
Android is an open-source mobile operating system that is based on the modified versions of Linux kernel. Though it was mainly designed for smartphones, now it is being used for Tablets, Televisions, Smartwatches, and other Android wearables.
2. Who is the inventor of Android Technology?
The inventors of Android Technology are- Andry Rubin, Nick Sears, and Rich Miner.
3. What is the latest version of Android?
The latest version of Android is Android 10.0, known as Android Q. The upcoming major Android release is Android 11, which is the 18th version of Android. [Note: Keep checking the versions, it is as of June 2020.]
4. How many Android versions can you recall right now?
Till now, there are 17 versions of Android, which have their names in alphabetical order. The 18th version of Android is also going to come later this year. The versions of Android are here:
- Android 1.0 – Its release is 23 September 2008.
- Android 1.1 – Its release date is 9 February 2009.
- Android 1.5 – Its name is Cupcake, Released on 27 April 2009.
- Android 1.6 – Its name is Donut, Released on 15 September 2009.
- Android 2.0 – Its name is Eclair, Released on 26 October 2009
- Android 2.2 – Its name is Froyo, Released on 20 May 2010.
- Android 2.3 – Its name is Gingerbread, Released on 06 December 2010.
- Android 3.0 – Its name is Honeycomb, Released on 22 February 2011.
- Android 4.0 – Its name is Ice Cream Sandwich, Released on 18 October 2011.
- Android 4.1 – Its name is Jelly Bean, Released on 9 July 2012.
- Android 4.4 – Its name is KitKat, Released on 31 October 2013.
- Android 5.0 – Its name is Lollipop, Released on 12 November 2014.
- Android 6.0 – Its name is Marshmallow, Released on 5 October 2015.
- Android 7.0 – Its name is Nougat, Released on 22 August 2016.
- Android 8.0 – Its name is Oreo, Released on 21 August 2017.
- Android 9.0 – Its name is Pie, Released on 6 August 2018.
- Android 10.0 – Its name is Android Q, Released on 3 September 2019.
- Android 11.0 – As of now, it is Android 11.
5. Explain the Android Architecture with its components.
This is a popular android developer interview question
Android Architecture consists of 5 components that are-
a. Linux Kernel: It is the foundation of the Android Architecture that resides at the lowest level. It provides the level of abstraction for hardware devices and upper layer components. Linux Kernel also provides various important hardware drivers that act as software interfaces for hardwares like camera, bluetooth, etc.
b. Native Libraries: These are the libraries for Android that are written in C/C++. These libraries are useful to build many core services like ART and HAL. It provides support for core features.
c. Android Runtime: It is an Android Runtime Environment. Android Operating System uses it during the execution of the app. It performs the translation of the application bytecode into the native instructions. The runtime environment of the device then executes these native instructions.
d. Application Framework: Application Framework provides many java classes and interfaces for app development. And it also provides various high-level services. This complete Application framework makes use of Java.
e. Applications: This is the topmost layer of Android Architecture. It provides applications for the end-user, so they can use the android device and compute the tasks.
6. What are the services that the Application framework provides?
The Android application framework has the following key services-
a. Activity Manager: It uses testing and debugging methods.
b. Content provider: It provides the data from application to other layers.
c. Resource Manager: This provides users access to resources.
d. Notification Manager: This gives notification to the users regarding actions taking place in the background.
e. View System: It is the base class for widgets, and it is also responsible for event handling.
7. What are the important features of Linux Kernel?
The important features of the Linux Kernel are as follows:
a. Power Management: Linux Kernel does power management to enhance and improve the battery life of the device.
b. Memory Management: It is useful for the maximum utilization of the available memory of the device.
c. Device Management: It includes managing all the hardware device drivers. It maximizes the utilization of the available resources.
d. Security: It ensures that no application has any such permission that it affects any other application in order to maintain security.
e. Multi-tasking: Multi-tasking provides the users the ease of doing multiple tasks at the same time.
8. What are the building blocks of an Android Application?
This is a popular android interview question for freshers.
The main components of any Android application are- Activity, Services, Content Provider, and Broadcast Receiver. You can understand them as follows:
a. Activity- It is a class that acts as the entry point representing a single screen to the user. It is like a window to show the user interface.
b. Services- Services are the longest-running component that runs in the background.
c. Content Provider- The content provider is an essential component that allows apps to share data between themselves.
d. Broadcast receivers- Broadcast receiver is another most crucial application component. It helps the apps to receive and respond to broadcast messages from the system or some other application.
9. What are the important components of Android Application?
The Components of Android application are listed below:
- Widgets
- Intents
- Views
- Notification
- Fragments
- Layout XML files
- Resources
10. What are the widgets?
Widgets are the variations of Broadcast receivers. They are an important part of home screen customization. They often display some data and also allow users to perform actions on them. Mostly they display the app icon on the screen.
11. Can you name some types of widgets?
Mentioned below are the types of widgets-
a. Informative Widgets: These widgets show some important information. Like, the clock widget or a weather widget.
b. Collective Widgets: They are the collection of some types of elements. For example, a music widget that lets us change, skip, or forward the song.
c. Control Widgets: These widgets help us control the actions within the application through it. Like an email widget that helps check the recent mails.
d. Hybrid Widgets: Hybrid widgets are those that consist of at least two or more types of widgets.
12. What are Intents?
Intents are an important part of Android Applications. They enable communication between components of the same application as well as separate applications. The Intent signals the Android system about a certain event that has occurred.
13. Explain the types of intents briefly?
Intent is of three types that are-
a. Implicit Intents: Implicit intents are those in which there is no description of the component name but only the action.
b. Explicit Intents: In explicit intents, the target component is present by declaring the name of the component.
c. Pending Intents: These are those intents that act as a shield over the Intent objects. It covers the intent objects and grants permission to the external app components to access them.
14. What is a View?
A view is an important building block that helps in designing the user interface of the application. It can be a rectangular box or a circular shape, for example, Text View, Edit Text, Buttons, etc. Views occupy a certain area of the screen, and it is also responsible for event handling. A view is the superclass of all the graphical user interface components.
15. What do you understand by View Group?
It is the subclass of the ViewClass. It gives an invisible container to hold layouts or views. You can understand view groups as special views that are capable of holding other views, that are Child View.
16. What do you understand about Shared Preferences?
It is a simple mechanism for data storage in Android. In this, there is no need to create files, and using APIs, it stores the data in XML files. It stores the data in the pair of key-values. SharedPreferences class lets the user save the values and retrieve them when required. Using SharedPreferences we can save primitive data like- boolean, float, integer, string and long.
17. What is a Notification?
A notification is just like a message that shows up outside the Application UI to provide reminders to the users. They remind the user about a message received, or some other timely information from the app.
18. Give names of Notification types.
There are three types of notifications namely-
a. Toast Notification- This notification is the one that fades away sometime after it pops up.
b. Status Notification- This notification stays till the user takes some action on it.
c. Dialog Notification- This notification is the result of an Active Activity.
19. What are fragments?
A fragment is a part of the complete user interface. These are present in Activity, and an activity can have one or more fragments at the same time. We can reuse a fragment in multiple activities as well.
20. What are the types of fragments?
There are three types of fragments that are: Single Fragment, List Fragment, Fragment Transactions.
- Single Transactions can only show a single view for the user.
- List Fragments have a special list view feature that provides a list from which the user can select one.
- Fragment Transactions are helpful for the transition between one fragment to the other.
Frequently asked Android Interview Questions and Answers
21. What are Layout XML files?
Layout XML files contain the structure for the user interface of the application. The XML file also contains various different layouts and views, and they also specify various GUI components that are there in Activity or fragments.
22. What are Resources in Android Application?
The resources in Android Apps defines images, texts, strings, colors, etc. Everything in resources directory is referenced in the source code of the app so that we can use them.
23. Can you develop Android Apps with languages other than Java? If so, name some.
Yes, there are many languages that we can work with, for the development of Android Applications. To name some, I would say Java, Python, C, C++, Kotlin, C#, Corona/LUA.
24. What are the states of the Activity Lifecycle?
Activity lifecycle has the following four stages-
a. Running State: As soon as the activity starts, it is the first state.
b. Paused State: When some other activity starts without closing the previous one, the running activity turns into the Paused state.
c. Resume State: When the activity opens again after being in pause state, it comes into the Resume State.
d. Stopped State: When the user closes the application or stops using it, the activity goes to the Stopped state.
25. What are some methods of Activity?
The methods of Activity are as follows:
- onCreate()
- onStart()
- onPause()
- onRestart()
- onResume()
- onStop()
- onDestroy()
26. How can you launch an activity in Android?
We launch an activity using Intents. For this we need to use intent as follows:
- ntent intent_name= new Intent(this, Activity_name.class);
- startActivity(intent_name);
27. What is the service lifecycle?
There are two states of a service that are-
a. Started State: This is when the service starts its execution. A Services come in start state only through the startService() method.
b. Bounded State: A service is in the bounded state when it calls the method bindService().
28. What are some methods of Services?
The methods of service are as follows-
- onStartCommand()
- onBind()
- onCreate()
- onUnbind()
- onDestroy()
- onRebind()
29. What are the types of Broadcast?
Broadcasts are of two types that are-
a. Ordered Broadcast: Ordered broadcasts are Synchronous and work in a proper order. It decides the order by using the priority assigned to the broadcasts.
b. Normal Broadcast: These are asynchronous and unordered. They are more efficient as they run unorderly and all at once. But, they lack full utilization of the results.
30. What are useful impotent folders in Android?
The impotent folders in an Android application are-
- build.xml- It is responsible for the build of Android applications.
- bin/ – The bin folder works as a staging area to wrap the files packages into the APK.
- src/ – The src is a folder where all the source files of the project are present.
- res/ – The res is the resource folder that stores values of the resources that are used in the application. These resources can be colors, styles, strings, dimensions, etc.
- assets/ – It provides a facility to include files like text, XML, fonts, music, and video in the Android application.
31. What are the important files for Android Application when working on Android Studio?
This is an important android studio interview question
There are following three files that we need to work on for an application to work-
a. The AndroidManifest.xml file: It has all the information about the application.
b. The MainActivity.java file: It is the app file that actually gets converted to the dalvik executable and runs the application. It is written in java.
c. The Activity_main.xml file: It is the layout file that is available in the res/layout directory. It is another mostly used file while developing the application.
32. Which database do you use for Android Application development?
The database that we use for Android Applications is SQLite. It is because SQLite is lightweight and specially developed for Android Apps. SQLite works the same way as SQL using the same commands.
33. Tell us some features of Android OS.
The best features of Android include-
- Multi-tasking
- Support for a great range of languages
- Support for split-screen
- High connectivity with 5G support
- Motion Control
34. Why did you learn Android development?
Learning Android Studio is a good idea because of the following-
- It has a low application development cost.
- It is an open-source platform.
- It has multi-platform support as well as Multi-carrier support.
- It is open for customizations.
- Android is a largely used operating system throughout the world.
35. What are the different ways of storage supported in Android?
The various storage ways supported in Android are as follows:
- Shared Preference
- Internal Storage
- External Storage
- SQLite Databases
- Network Connection
36. What are layouts?
Layout is nothing but arrangements of elements on the device screen. These elements can be images, tests, videos, anything. They basically define the structure of the Android user interface to make it user friendly.
37. How many layout types are there?
The type of layouts used in Android Apps are as follows:
- Linear Layout
- Relative Layout
- Constraint Layout
- Table Layout
- Frame Layout
- Absolute Layout
- Scrollview layout
38. What is an APK?
An APK stands for Android Package that is a file format of Android Applications. Android OS uses this package for the distribution and installation of the Android Application.
39. What is an Android Manifest file?
The manifest file describes all the essential information about the project application for build tools, Android operating system, and google play. This file is a must for every Android project that we develop, and it is present in the root of the project source set.
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