山岸  英樹

山岸 英樹

1634016360

Javascriptのif、else、elseifステートメントは何ですか?

このチュートリアルを通じて、if、else、else ifステートメントとは何か、およびJavaScriptの使用方法を学習します。

javascript条件ステートメントは最もよく使用されるステートメントです。プログラミングでいくつかの条件付きの状況に直面したとき。ある条件が満たされたときに実行されるコードの特定のブロック。

このチュートリアルでは、以下について説明します。

  • 条件文とは何ですか?
  • JavaScriptの条件文のタイプのタイプ
    • Ifステートメント
    • If…Elseステートメント
    • If…ElseIf…Elseステートメント

条件文とは何ですか?

条件付きステートメントは、意思決定ステートメントとも呼ばれます。これは、決定を下すために使用され、特定の条件に基づいてコードのブロックを実行します。

JavaScriptの条件文のタイプ

JavaScriptには、決定を下すために使用できる主に3つのタイプの条件ステートメントがあります。

  • もし 声明
  • もし... ELSE 文の
  • もし...他にあれば... .ELSE 声明

If 声明

条件が真の場合、ifステートメントはコードのブロックを実行します。

構文

if (test condition)
{
    code to be executed if condition is true
}

Ifステートメントのフローチャート

Ifステートメントのフローチャート

Ifステートメントの例

ifステートメントの例を取り上げ、ifステートメントを使用して特定の条件のみをチェックしてみましょう。


<html>
<head>
  <title>IF Statments!!!</title>
  <script type="text/javascript">
    var num = prompt("Solve :- 8+5");
    if(num == 13)
    document.write("Correct answer <br />");
    if(num == 13)
    document.write("Wrong answer <br />");
  </script>
</head>
<body>
</body>
</html>

上記の例では、javascriptポップアップメソッドを使用してユーザーからの入力を取得しています。

If Else 声明

ifテスト条件がfalseと評価されたとき。次に、コードのelseステートメントブロックを実行します。

構文

if (test condition)
{
    code to be executed if condition is true
}
else
{
   code to be executed if condition is false
}

IfElseステートメントのフローチャート

Ifelseステートメントのフローチャート

ifステートメントの例

IfElseステートメントの例を見てみましょう。

<html>
<head>
  <title>IF ELSE Statments!!!</title>
  <script type="text/javascript">
    var num = 13;
    if(num == 12){  
      document.write("Execute If Statement<br />");
    }else{
      document.write("Execute Else Statement<br />");
    }
  </script>
</head>
<body>
</body>
</html>

If..Else If..Else 声明

ifステートメントの後に複数の条件をテストする場合。次に、ElseIfステートメントを使用します。

構文

if (test condition1)
{

code to be executed if condition1 is true

}
else if(test condition2)
{

lines of code to be executed if condition2 is true

}
else
{

code to be executed if condition1 is false and condition2 is false

}

If Else IfElseステートメントの例

ifステートメントの例を取り上げて、複数の条件を確認してみましょう。

<html>
<head>
  <title>IF ELSE If Else Statments!!!</title>
  <script type="text/javascript">
    var num = 13;
    if(num == 12){  
      document.write("Execute If Statement<br />");
    }else if(num == 13){
      document.write("Execute Else If Statement<br />");
    }else{
      document.write("Execute Else Statement<br />");
    }
  </script>
</head>
<body>
</body>
</html>

リンク: https://www.tutsmake.com/javascript-if-else-else-if-statements-example/

#javascript 

 

What is GEEK

Buddha Community

Javascriptのif、else、elseifステートメントは何ですか?
Lowa Alice

Lowa Alice

1624402800

JavaScript if else (tutorial). DO NOT MISS!!!

JavaScript if else made simple.

📺 The video in this post was made by Programming with Mosh
The origin of the article: https://www.youtube.com/watch?v=IsG4Xd6LlsM&list=PLTjRvDozrdlxEIuOBZkMAK5uiqp8rHUax&index=7
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Thanks for visiting and watching! Please don’t forget to leave a like, comment and share!

#javascript #if else #javascript if else #javascript if else (tutorial)

Kasey  Turcotte

Kasey Turcotte

1623141234

The Most Efficient if-elif-else in Pandas

And why I (and you as well) have probably been writing them inefficiently

Simple if else statements are a staple of every programming language. With Numpy and Pandas introducing unparalleled speed to Python enthusiasts, it was clear that people were going to need to create an if-elif-else feature that could be vectorized and efficiently applied to any specific column in your dataset. However, even though this would seem to be the case, if you actually google the best method of doing this… there really is no clear answer. Some users claim using loc and iloc are the fastest, others claim that pandas.where() is fastest , and some users even claim that list comprehension is the simplest and most efficient method. There is no proof to these claims, just users sharing the method they use to accomplish this seemingly simple task. Because of this, I scavenged the internet testing every single method that could accomplish the task, and the winner was not at all what I initially expected.

#data-science #if-else #python-programming #pandas #optimization #the most efficient if-elif-else in pandas

Deno Developer

Deno Developer

1634095849

Deno v1.15 Has Been Released

Deno 1.15 improves Web Crypto support, adds deno uninstall subcommand, stabilizes URLPattern and more.

Deno 1.15 has been tagged and released with the following features and changes:

If you already have Deno installed, you can upgrade to 1.15 by running

deno upgrade

If you are installing Deno for the first time, you can use one of the methods listed below:

# Using Shell (macOS and Linux):
curl -fsSL https://deno.land/x/install/install.sh | sh

# Using PowerShell (Windows):
iwr https://deno.land/x/install/install.ps1 -useb | iex

# Using Homebrew (macOS):
brew install deno

# Using Scoop (Windows):
scoop install deno

# Using Chocolatey (Windows):
choco install deno

New features

New crypto APIs

In line with our goal to have a feature complete Web Crypto API by the end of the year, we have made good progress this release:

  • crypto.subtle.exportKey():
    • RSA keys can now be exported in spki format.
  • crypto.subtle.importKey():
    • ECDSA keys can now be imported in raw format.
  • crypto.subtle.deriveBits():
    • ECDH derivation is now supported (only for P256 keys).
  • crypto.subtle.wrapKey():
    • Key wrapping is now supported for all key & format combinations supported by crypto.subtle.exportKey().
  • crypto.subtle.encrypt():
    • AES-CBC encryption is now supported.
  • crypto.subtle.decrypt():
    • AES-CBC decryption is now supported.

You can subscribe to this tracking issue to be notified of further progress on the Web Crypto API.

Thanks to Divy Srivastava for the significant work on the Web Crypto implementation in Deno.

FFI improvements

FFI was added in Deno 1.13, this API allows users to call libraries written in languages that support C ABI such as C, C++, C#, Kotlin, Nim, Rust or Zig.

This release adds support for two very useful features to FFI API: non-blocking calls and buffer arguments.

Non-blocking calls

There are many use cases where users might want to run CPU-bound FFI functions in the background without blocking other tasks on the main thread.

With this release symbols can be marked nonblocking in Deno.dlopen. These function calls will run on a dedicated blocking thread and will return a Promise resolving to the desired result.

Example of executing expensive FFI calls with Deno:

// sleep.c
#ifdef _WIN32
#include <Windows.h>
#else
#include <time.h>
#endif

int sleep(unsigned int ms) {
  #ifdef _WIN32
  Sleep(ms);
  #else
  struct timespec ts;
  ts.tv_sec = ms / 1000;
  ts.tv_nsec = (ms % 1000) * 1000000;
  nanosleep(&ts, NULL);
  #endif
}

Calling it from Deno:

// nonblocking_ffi.ts
const library = Deno.dlopen("./sleep.so", {
  sleep: {
    parameters: ["usize"],
    result: "void",
    nonblocking: true,
  },
});

library.symbols.sleep(500).then(() => console.log("After"));
console.log("Before");

Result:

$ deno run --allow-ffi --unstable nonblocking_ffi.ts
Before
After

Buffer arguments

Prior to 1.15 arguments to FFI symbols were limited to primitive types, but this release adds support for using buffers as arguments for FFI calls.

When calling FFI symbols with a buffer, the next argument must be buffer's length.

Example:

// print_buffer.rs
#[no_mangle]
pub extern "C" fn print_buffer(ptr: *const u8, len: usize) {
  let buf = unsafe { std::slice::from_raw_parts(ptr, len) };
  println!("{:?}", buf);
}

Calling it from Deno:

// print_buffer.ts
const library = Deno.dlopen("./print_buffer.so", {
  print_buffer: {
    parameters: ["buffer", "usize"],
    result: "void",
  },
});

const buffer = new Uint8Array([1, 2, 3, 4, 5, 6, 7, 8]);
dylib.symbols.print_buffer(buffer, buffer.length);

Result:

$ deno run --allow-ffi --unstable print_buffer.ts
[1, 2, 3, 4, 5, 6, 7, 8]

In addition to passing buffers-as-arg, we recognize the importance of being able to use buffers-as-return-value and plan to support this feature in the coming releases.

For more information on the FFI API visit manual page.

Thanks to Elias Sjögreen and Divy Srivastava for implementing these features.

deno uninstall command

This release introduces a deno uninstall subcommand. It lets you remove a command previously installed with deno install.

$ deno install
Check https://deno.land/std/examples/welcome.ts
✅ Successfully installed welcome
/Users/lucacasonato/.deno/bin/welcome
$ welcome
Welcome to Deno!
$ deno uninstall welcome
deleted /Users/lucacasonato/.deno/bin/welcome
✅ Successfully uninstalled welcome

Uninstalling a command was previously already possible by just removing the command file from the .deno/bin directory.

deno lint --watch

deno lint now supports the --watch flag that will keep the process alive after printing diagnostics and watch for file changes to update diagnostics from changed files.

As in other subcommands that support --watch flag, the files that are needed to be watched are automatically discovered by Deno.

Thanks to @CGQAQ who contributed this feature.

In memory CA certificates

Over the past year, Deno has accumulated 3 different APIs that all deal with TLS: Deno.connectTls for establishing outbound TLS connections, Deno.startTls for upgrading existing connections to TLS, and Deno.createHttpClient for changing HTTP and TLS settings for outbound HTTP requests.

All of these three APIs had various ways to specify custom CA certificates. This has now been unified. All three APIs now take a caCerts option. This property must be given as an array of strings, where each string is a PEM encoded X.509 certificate. Multiple certificates can be specified in this array.

An example:

const caCert = await Deno.readTextFile("./custom_ca_cert.pem");
const client = Deno.connectTls({
  hostname: "database.internal",
  port: 4443,
  caCerts: [caCert],
});

This release also removes the unstable caData option from Deno.createHttpClient because this new API replaces it.

Nested testing API

This release adds a new experimental sub-steps API to the Deno testing framework. This addition allows users to define sub-steps for tests defined by Deno.test. These sub steps get their own sanitizer scopes and are rendered in the test runner with indents. The new API is general enough so it can be wrapped by polyfills to emulate existing test frameworks like mocha or node-tap. The original explainer for this new API explains it in more detail.

Here is an example of a test that uses the new API. It creates a database connection, runs some queries against it in sub tests and then closes the connection.

Deno.test("database test", async (t) => {
  const db = await Database.connect("postgres://localhost/test");

  await t.step("insert user", async () => {
    const users = await db.query(
      "INSERT INTO users (name) VALUES ('Deno') RETURNING *",
    );
    assertEquals(users.length, 1);
    assertEquals(users[0].name, "Deno");
  });

  await t.step("insert book", async () => {
    const books = await db.query(
      "INSERT INTO books (name) VALUES ('The Deno Manual') RETURNING *",
    );
    assertEquals(books.length, 1);
    assertEquals(books[0].name, "The Deno Manual");
  });

  db.close();
});

The same test written in Mocha style would look like this:

describe("database test", () => {
  let db: Database;

  beforeAll(async () => {
    db = await Database.connect("postgres://localhost/test");
  });

  it("insert user", async () => {
    const users = await db!.query(
      "INSERT INTO users (name) VALUES ('Deno') RETURNING *",
    );
    assertEquals(users.length, 1);
    assertEquals(users[0].name, "Deno");
  });

  it("insert book", async () => {
    const books = await db!.query(
      "INSERT INTO books (name) VALUES ('The Deno Manual') RETURNING *",
    );
    assertEquals(books.length, 1);
    assertEquals(books[0].name, "The Deno Manual");
  });

  afterAll(() => {
    db!.close();
  });
});

For those more familiar with this style, we have written a simple polyfill for Mocha that builds on top of this new API: https://gist.github.com/lucacasonato/54c03bb267074aaa9b32415dbfb25522.

Inline with this polyfill, we now have some examples showcasing how to use chai or sinon for assertions in Deno tests:

Please note that this API is still experimental and may change in the future. Feedback on this API is very welcome!

API stabilizations

1.15 brings stabilization of several Deno APIs:

  • Deno.kill
  • Deno.Process.kill
  • Deno.resolveDns

Using these APIs no longer requires passing --unstable flag on the CLI.

We plan to stabilize the Deno.signal() API in the upcoming release.

Stabilization of URLPattern API in sync with Chromium

Last release introduced a new unstable web platform API for matching URLs against patterns. URLPattern is a builtin alternative to the popular path-to-regexp library.

The pattern syntax is very similar to path-to-regexp. What sets URLPattern apart is that it is capable of matching more than just paths - it can match each part of a URL (protocol, hostname, pathname, query string, hash, etc.) individually.

This release stabilizes this API in sync with Chromium. It will be available today in Deno 1.15, and on October 19th in the 95 release of Google Chrome and Microsoft Edge.

Documentation and examples are available on MDN: https://developer.mozilla.org/en-US/docs/Web/API/URLPattern.

V8 9.5 update

Deno 1.15 includes V8 9.5. This release introduces the new "Intl.DisplayNames v2" JavaScript API, an extended timeZoneName option for Intl.DateTimeFormat, and support for the "WebAssembly Exception Handling (Wasm EH) proposal".

Details about each change are available in the V8 9.5 release notes.

Improving Node Compatibility

To make it easier to run Node programs in Deno, a new flag --compat was added (this flag requires --unstable). When this flag is present Deno will automatically set up Node global variables (like process) and provide all built-in modules available in Node. This means Deno can now handle code like this:

import { readFileSync } from "fs";
let passwd = readFileSync("/etc/passwd", "utf-8");
console.log(passwd);
console.log(process.pid);

This release is just the first pass for --compat. We will be putting a lot of work into improving compat mode in coming releases, working towards Node emulation.

std/node is a module that provides a compatibility layer for Node APIs, making it possible to run a subset of Node programs in Deno. The release of std 0.111.0 brings a big update to this compatibility layer, including addition of some highly desired modules (dns, http and net), as well as many updates to the crypto module.

Original article source at https://deno.com

#deno 

山岸  英樹

山岸 英樹

1634016360

Javascriptのif、else、elseifステートメントは何ですか?

このチュートリアルを通じて、if、else、else ifステートメントとは何か、およびJavaScriptの使用方法を学習します。

javascript条件ステートメントは最もよく使用されるステートメントです。プログラミングでいくつかの条件付きの状況に直面したとき。ある条件が満たされたときに実行されるコードの特定のブロック。

このチュートリアルでは、以下について説明します。

  • 条件文とは何ですか?
  • JavaScriptの条件文のタイプのタイプ
    • Ifステートメント
    • If…Elseステートメント
    • If…ElseIf…Elseステートメント

条件文とは何ですか?

条件付きステートメントは、意思決定ステートメントとも呼ばれます。これは、決定を下すために使用され、特定の条件に基づいてコードのブロックを実行します。

JavaScriptの条件文のタイプ

JavaScriptには、決定を下すために使用できる主に3つのタイプの条件ステートメントがあります。

  • もし 声明
  • もし... ELSE 文の
  • もし...他にあれば... .ELSE 声明

If 声明

条件が真の場合、ifステートメントはコードのブロックを実行します。

構文

if (test condition)
{
    code to be executed if condition is true
}

Ifステートメントのフローチャート

Ifステートメントのフローチャート

Ifステートメントの例

ifステートメントの例を取り上げ、ifステートメントを使用して特定の条件のみをチェックしてみましょう。


<html>
<head>
  <title>IF Statments!!!</title>
  <script type="text/javascript">
    var num = prompt("Solve :- 8+5");
    if(num == 13)
    document.write("Correct answer <br />");
    if(num == 13)
    document.write("Wrong answer <br />");
  </script>
</head>
<body>
</body>
</html>

上記の例では、javascriptポップアップメソッドを使用してユーザーからの入力を取得しています。

If Else 声明

ifテスト条件がfalseと評価されたとき。次に、コードのelseステートメントブロックを実行します。

構文

if (test condition)
{
    code to be executed if condition is true
}
else
{
   code to be executed if condition is false
}

IfElseステートメントのフローチャート

Ifelseステートメントのフローチャート

ifステートメントの例

IfElseステートメントの例を見てみましょう。

<html>
<head>
  <title>IF ELSE Statments!!!</title>
  <script type="text/javascript">
    var num = 13;
    if(num == 12){  
      document.write("Execute If Statement<br />");
    }else{
      document.write("Execute Else Statement<br />");
    }
  </script>
</head>
<body>
</body>
</html>

If..Else If..Else 声明

ifステートメントの後に複数の条件をテストする場合。次に、ElseIfステートメントを使用します。

構文

if (test condition1)
{

code to be executed if condition1 is true

}
else if(test condition2)
{

lines of code to be executed if condition2 is true

}
else
{

code to be executed if condition1 is false and condition2 is false

}

If Else IfElseステートメントの例

ifステートメントの例を取り上げて、複数の条件を確認してみましょう。

<html>
<head>
  <title>IF ELSE If Else Statments!!!</title>
  <script type="text/javascript">
    var num = 13;
    if(num == 12){  
      document.write("Execute If Statement<br />");
    }else if(num == 13){
      document.write("Execute Else If Statement<br />");
    }else{
      document.write("Execute Else Statement<br />");
    }
  </script>
</head>
<body>
</body>
</html>

リンク: https://www.tutsmake.com/javascript-if-else-else-if-statements-example/

#javascript 

 

Python If Else Statement: How to Use Conditional Statement

Python If Else Statement is logical statements. Python supports the usual logical conditions in mathematics. The decision-making process is required when we want to execute code only if a specific condition is satisfied. The conditional if…elif…else statement is used in the Python programming language for decision making.

There come situations in real-life when we need to make some decisions, and based on those decisions, we decide what should we do next. Similar situations arise in the programming also where we need to make some decisions, and based on this decision; we will execute the next block of code.

Python If Else Statement

Conditional Statement in Python performs different computations or actions depending on whether the specific Boolean constraint evaluates to true or false. Conditional statements are handled by the if statements in Python.

#python #if..elif..else #programming #python if else statement