How to Bash Read Command

Bash has no built-in function to take the user’s input from the terminal. The read command of Bash is used to take the user’s input from the terminal. This command has different options to take an input from the user in different ways. Multiple inputs can be taken using the single read command. Different ways of using this command in the Bash script are described in this tutorial.

Syntax

read [options] [var1, var2, var3…]

The read command can be used without any argument or option. Many types of options can be used with this command to take the input of the particular data type. It can take more input from the user by defining the multiple variables with this command.

Some Useful Options of the Read Command

Some options of the read command require an additional parameter to use. The most commonly used options of the read command are mentioned in the following:

OptionPurpose
-d <delimiter>It is used to take the input until the delimiter value is provided.
-n <number>It is used to take the input of a particular number of characters from the terminal and stop taking the input earlier based on the delimiter.
-N <number>It is used to take the input of the particular number of characters from the terminal, ignoring the delimiter.
-p <prompt>It is used to print the output of the prompt message before taking the input.
-sIt is used to take the input without an echo. This option is mainly used to take the input for the password input.
-aIt is used to take the input for the indexed array.
-t <time>It is used to set a time limit for taking the input.
-u <file descriptor>It is used to take the input from the file.
-rIt is used to disable the backslashes.

 

Different Examples of the Read Command

The uses of read command with different options are shown in this part of this tutorial.

Example 1: Using Read Command without Any Option and variable

Create a Bash file with the following script that takes the input from the terminal using the read command without any option and variable. If no variable is used with the read command, the input value is stored in the $REPLY variable. The value of this variable is printed later after taking the input.

#!/bin/bash  
#Print the prompt message
echo "Enter your favorite color: "  
#Take the input
read  
#Print the input value
echo "Your favorite color is $REPLY"

Output:

The following output appears if the “Blue” value is taken as an input:

Example 2: Using Read Command with a Variable

Create a Bash file with the following script that takes the input from the terminal using the read command with a variable. The method of taking the single or multiple variables using a read command is shown in this example. The values of all variables are printed later.

#!/bin/bash  
#Print the prompt message
echo "Enter the product name: "  
#Take the input with a single variable
read item

#Print the prompt message
echo "Enter the color variations of the product: "  
#Take three input values in three variables
read color1 color2 color3

#Print the input value
echo "The product name is $item."  
#Print the input values
echo "Available colors are $color1, $color2, and $color3."

Output:

The following output appears after taking a single input first and three inputs later:

Example 3: Using Read Command with -p Option

Create a Bash file with the following script that takes the input from the terminal using the read command with a variable and the -p option. The input value is printed later.

#!/bin/bash  
#Take the input with the prompt message
read -p "Enter the book name: " book
#Print the input value
echo "Book name: $book"

Output:

The following output appears after taking the input:

Example 4: Using Read Command with -s Option

Create a Bash file with the following script that takes the input from the terminal using the read command with a variable and the -s option. The input value of the password will not be displayed for the -s option. The input values are checked later for authentication. A success or failure message is also printed.

#!/bin/bash  
#Take the input with the prompt message
read -p "Enter your email: " email
#Take the secret input with the prompt message
read -sp "Enter your password: " password

#Add newline
echo ""

#Check the email and password for authentication
if [[ $email == "admin@example.com" && $password == "secret" ]]
then
   #Print the success message
   echo "Authenticated."
else
   #Print the failure message
   echo "Not authenticated."
fi

Output:

The following output appears after taking the valid and invalid input values:

Example 5: Using Read Command with -a Option

Create a Bash file with the following script that takes the input from the terminal using the read command with a variable and the -a option. The array values are printed later after taking the input values from the terminal.

#!/bin/bash  
echo "Enter the country names: "  
#Take multiple inputs using an array  
read -a countries

echo "Country names are:"
#Read the array values
for country in ${countries[@]}
do
    echo $country
done

Output:

The following output appears after taking the array values:

Example 6: Using Read Command with -n Option

Create a Bash file with the following script that takes the input from the terminal using the read command with a variable and the -n option.

#!/bin/bash  
#Print the prompt message
echo "Enter the product code: "  
#Take the input of five characters
read -n 5 code
#Add newline
echo ""
#Print the input value
echo "The product code is $code"

Output:

The following output appears if the “78342” value is taken as input:

Example 7: Using Read Command with -t Option

Create a Bash file with the following script that takes the input from the terminal using the read command with a variable and the -t option.

#!/bin/bash  
#Print the prompt message
echo -n "Write the result of 10-6: "  
#Take the input of five characters
read -t 3 answer

#Check the input value
if [[ $answer == "4" ]]
then
   echo "Correct answer."
else
   echo "Incorrect answer."
fi

Output:

The following output appears after taking the correct and incorrect input values:

Conclusion

The uses of some useful options of the read command are explained in this tutorial using multiple examples to know the basic uses of the read command.

Original article source at: https://linuxhint.com/

#bash #command 

Chloe  Butler

Chloe Butler

1667425440

Pdf2gerb: Perl Script Converts PDF Files to Gerber format

pdf2gerb

Perl script converts PDF files to Gerber format

Pdf2Gerb generates Gerber 274X photoplotting and Excellon drill files from PDFs of a PCB. Up to three PDFs are used: the top copper layer, the bottom copper layer (for 2-sided PCBs), and an optional silk screen layer. The PDFs can be created directly from any PDF drawing software, or a PDF print driver can be used to capture the Print output if the drawing software does not directly support output to PDF.

The general workflow is as follows:

  1. Design the PCB using your favorite CAD or drawing software.
  2. Print the top and bottom copper and top silk screen layers to a PDF file.
  3. Run Pdf2Gerb on the PDFs to create Gerber and Excellon files.
  4. Use a Gerber viewer to double-check the output against the original PCB design.
  5. Make adjustments as needed.
  6. Submit the files to a PCB manufacturer.

Please note that Pdf2Gerb does NOT perform DRC (Design Rule Checks), as these will vary according to individual PCB manufacturer conventions and capabilities. Also note that Pdf2Gerb is not perfect, so the output files must always be checked before submitting them. As of version 1.6, Pdf2Gerb supports most PCB elements, such as round and square pads, round holes, traces, SMD pads, ground planes, no-fill areas, and panelization. However, because it interprets the graphical output of a Print function, there are limitations in what it can recognize (or there may be bugs).

See docs/Pdf2Gerb.pdf for install/setup, config, usage, and other info.


pdf2gerb_cfg.pm

#Pdf2Gerb config settings:
#Put this file in same folder/directory as pdf2gerb.pl itself (global settings),
#or copy to another folder/directory with PDFs if you want PCB-specific settings.
#There is only one user of this file, so we don't need a custom package or namespace.
#NOTE: all constants defined in here will be added to main namespace.
#package pdf2gerb_cfg;

use strict; #trap undef vars (easier debug)
use warnings; #other useful info (easier debug)


##############################################################################################
#configurable settings:
#change values here instead of in main pfg2gerb.pl file

use constant WANT_COLORS => ($^O !~ m/Win/); #ANSI colors no worky on Windows? this must be set < first DebugPrint() call

#just a little warning; set realistic expectations:
#DebugPrint("${\(CYAN)}Pdf2Gerb.pl ${\(VERSION)}, $^O O/S\n${\(YELLOW)}${\(BOLD)}${\(ITALIC)}This is EXPERIMENTAL software.  \nGerber files MAY CONTAIN ERRORS.  Please CHECK them before fabrication!${\(RESET)}", 0); #if WANT_DEBUG

use constant METRIC => FALSE; #set to TRUE for metric units (only affect final numbers in output files, not internal arithmetic)
use constant APERTURE_LIMIT => 0; #34; #max #apertures to use; generate warnings if too many apertures are used (0 to not check)
use constant DRILL_FMT => '2.4'; #'2.3'; #'2.4' is the default for PCB fab; change to '2.3' for CNC

use constant WANT_DEBUG => 0; #10; #level of debug wanted; higher == more, lower == less, 0 == none
use constant GERBER_DEBUG => 0; #level of debug to include in Gerber file; DON'T USE FOR FABRICATION
use constant WANT_STREAMS => FALSE; #TRUE; #save decompressed streams to files (for debug)
use constant WANT_ALLINPUT => FALSE; #TRUE; #save entire input stream (for debug ONLY)

#DebugPrint(sprintf("${\(CYAN)}DEBUG: stdout %d, gerber %d, want streams? %d, all input? %d, O/S: $^O, Perl: $]${\(RESET)}\n", WANT_DEBUG, GERBER_DEBUG, WANT_STREAMS, WANT_ALLINPUT), 1);
#DebugPrint(sprintf("max int = %d, min int = %d\n", MAXINT, MININT), 1); 

#define standard trace and pad sizes to reduce scaling or PDF rendering errors:
#This avoids weird aperture settings and replaces them with more standardized values.
#(I'm not sure how photoplotters handle strange sizes).
#Fewer choices here gives more accurate mapping in the final Gerber files.
#units are in inches
use constant TOOL_SIZES => #add more as desired
(
#round or square pads (> 0) and drills (< 0):
    .010, -.001,  #tiny pads for SMD; dummy drill size (too small for practical use, but needed so StandardTool will use this entry)
    .031, -.014,  #used for vias
    .041, -.020,  #smallest non-filled plated hole
    .051, -.025,
    .056, -.029,  #useful for IC pins
    .070, -.033,
    .075, -.040,  #heavier leads
#    .090, -.043,  #NOTE: 600 dpi is not high enough resolution to reliably distinguish between .043" and .046", so choose 1 of the 2 here
    .100, -.046,
    .115, -.052,
    .130, -.061,
    .140, -.067,
    .150, -.079,
    .175, -.088,
    .190, -.093,
    .200, -.100,
    .220, -.110,
    .160, -.125,  #useful for mounting holes
#some additional pad sizes without holes (repeat a previous hole size if you just want the pad size):
    .090, -.040,  #want a .090 pad option, but use dummy hole size
    .065, -.040, #.065 x .065 rect pad
    .035, -.040, #.035 x .065 rect pad
#traces:
    .001,  #too thin for real traces; use only for board outlines
    .006,  #minimum real trace width; mainly used for text
    .008,  #mainly used for mid-sized text, not traces
    .010,  #minimum recommended trace width for low-current signals
    .012,
    .015,  #moderate low-voltage current
    .020,  #heavier trace for power, ground (even if a lighter one is adequate)
    .025,
    .030,  #heavy-current traces; be careful with these ones!
    .040,
    .050,
    .060,
    .080,
    .100,
    .120,
);
#Areas larger than the values below will be filled with parallel lines:
#This cuts down on the number of aperture sizes used.
#Set to 0 to always use an aperture or drill, regardless of size.
use constant { MAX_APERTURE => max((TOOL_SIZES)) + .004, MAX_DRILL => -min((TOOL_SIZES)) + .004 }; #max aperture and drill sizes (plus a little tolerance)
#DebugPrint(sprintf("using %d standard tool sizes: %s, max aper %.3f, max drill %.3f\n", scalar((TOOL_SIZES)), join(", ", (TOOL_SIZES)), MAX_APERTURE, MAX_DRILL), 1);

#NOTE: Compare the PDF to the original CAD file to check the accuracy of the PDF rendering and parsing!
#for example, the CAD software I used generated the following circles for holes:
#CAD hole size:   parsed PDF diameter:      error:
#  .014                .016                +.002
#  .020                .02267              +.00267
#  .025                .026                +.001
#  .029                .03167              +.00267
#  .033                .036                +.003
#  .040                .04267              +.00267
#This was usually ~ .002" - .003" too big compared to the hole as displayed in the CAD software.
#To compensate for PDF rendering errors (either during CAD Print function or PDF parsing logic), adjust the values below as needed.
#units are pixels; for example, a value of 2.4 at 600 dpi = .0004 inch, 2 at 600 dpi = .0033"
use constant
{
    HOLE_ADJUST => -0.004 * 600, #-2.6, #holes seemed to be slightly oversized (by .002" - .004"), so shrink them a little
    RNDPAD_ADJUST => -0.003 * 600, #-2, #-2.4, #round pads seemed to be slightly oversized, so shrink them a little
    SQRPAD_ADJUST => +0.001 * 600, #+.5, #square pads are sometimes too small by .00067, so bump them up a little
    RECTPAD_ADJUST => 0, #(pixels) rectangular pads seem to be okay? (not tested much)
    TRACE_ADJUST => 0, #(pixels) traces seemed to be okay?
    REDUCE_TOLERANCE => .001, #(inches) allow this much variation when reducing circles and rects
};

#Also, my CAD's Print function or the PDF print driver I used was a little off for circles, so define some additional adjustment values here:
#Values are added to X/Y coordinates; units are pixels; for example, a value of 1 at 600 dpi would be ~= .002 inch
use constant
{
    CIRCLE_ADJUST_MINX => 0,
    CIRCLE_ADJUST_MINY => -0.001 * 600, #-1, #circles were a little too high, so nudge them a little lower
    CIRCLE_ADJUST_MAXX => +0.001 * 600, #+1, #circles were a little too far to the left, so nudge them a little to the right
    CIRCLE_ADJUST_MAXY => 0,
    SUBST_CIRCLE_CLIPRECT => FALSE, #generate circle and substitute for clip rects (to compensate for the way some CAD software draws circles)
    WANT_CLIPRECT => TRUE, #FALSE, #AI doesn't need clip rect at all? should be on normally?
    RECT_COMPLETION => FALSE, #TRUE, #fill in 4th side of rect when 3 sides found
};

#allow .012 clearance around pads for solder mask:
#This value effectively adjusts pad sizes in the TOOL_SIZES list above (only for solder mask layers).
use constant SOLDER_MARGIN => +.012; #units are inches

#line join/cap styles:
use constant
{
    CAP_NONE => 0, #butt (none); line is exact length
    CAP_ROUND => 1, #round cap/join; line overhangs by a semi-circle at either end
    CAP_SQUARE => 2, #square cap/join; line overhangs by a half square on either end
    CAP_OVERRIDE => FALSE, #cap style overrides drawing logic
};
    
#number of elements in each shape type:
use constant
{
    RECT_SHAPELEN => 6, #x0, y0, x1, y1, count, "rect" (start, end corners)
    LINE_SHAPELEN => 6, #x0, y0, x1, y1, count, "line" (line seg)
    CURVE_SHAPELEN => 10, #xstart, ystart, x0, y0, x1, y1, xend, yend, count, "curve" (bezier 2 points)
    CIRCLE_SHAPELEN => 5, #x, y, 5, count, "circle" (center + radius)
};
#const my %SHAPELEN =
#Readonly my %SHAPELEN =>
our %SHAPELEN =
(
    rect => RECT_SHAPELEN,
    line => LINE_SHAPELEN,
    curve => CURVE_SHAPELEN,
    circle => CIRCLE_SHAPELEN,
);

#panelization:
#This will repeat the entire body the number of times indicated along the X or Y axes (files grow accordingly).
#Display elements that overhang PCB boundary can be squashed or left as-is (typically text or other silk screen markings).
#Set "overhangs" TRUE to allow overhangs, FALSE to truncate them.
#xpad and ypad allow margins to be added around outer edge of panelized PCB.
use constant PANELIZE => {'x' => 1, 'y' => 1, 'xpad' => 0, 'ypad' => 0, 'overhangs' => TRUE}; #number of times to repeat in X and Y directions

# Set this to 1 if you need TurboCAD support.
#$turboCAD = FALSE; #is this still needed as an option?

#CIRCAD pad generation uses an appropriate aperture, then moves it (stroke) "a little" - we use this to find pads and distinguish them from PCB holes. 
use constant PAD_STROKE => 0.3; #0.0005 * 600; #units are pixels
#convert very short traces to pads or holes:
use constant TRACE_MINLEN => .001; #units are inches
#use constant ALWAYS_XY => TRUE; #FALSE; #force XY even if X or Y doesn't change; NOTE: needs to be TRUE for all pads to show in FlatCAM and ViewPlot
use constant REMOVE_POLARITY => FALSE; #TRUE; #set to remove subtractive (negative) polarity; NOTE: must be FALSE for ground planes

#PDF uses "points", each point = 1/72 inch
#combined with a PDF scale factor of .12, this gives 600 dpi resolution (1/72 * .12 = 600 dpi)
use constant INCHES_PER_POINT => 1/72; #0.0138888889; #multiply point-size by this to get inches

# The precision used when computing a bezier curve. Higher numbers are more precise but slower (and generate larger files).
#$bezierPrecision = 100;
use constant BEZIER_PRECISION => 36; #100; #use const; reduced for faster rendering (mainly used for silk screen and thermal pads)

# Ground planes and silk screen or larger copper rectangles or circles are filled line-by-line using this resolution.
use constant FILL_WIDTH => .01; #fill at most 0.01 inch at a time

# The max number of characters to read into memory
use constant MAX_BYTES => 10 * M; #bumped up to 10 MB, use const

use constant DUP_DRILL1 => TRUE; #FALSE; #kludge: ViewPlot doesn't load drill files that are too small so duplicate first tool

my $runtime = time(); #Time::HiRes::gettimeofday(); #measure my execution time

print STDERR "Loaded config settings from '${\(__FILE__)}'.\n";
1; #last value must be truthful to indicate successful load


#############################################################################################
#junk/experiment:

#use Package::Constants;
#use Exporter qw(import); #https://perldoc.perl.org/Exporter.html

#my $caller = "pdf2gerb::";

#sub cfg
#{
#    my $proto = shift;
#    my $class = ref($proto) || $proto;
#    my $settings =
#    {
#        $WANT_DEBUG => 990, #10; #level of debug wanted; higher == more, lower == less, 0 == none
#    };
#    bless($settings, $class);
#    return $settings;
#}

#use constant HELLO => "hi there2"; #"main::HELLO" => "hi there";
#use constant GOODBYE => 14; #"main::GOODBYE" => 12;

#print STDERR "read cfg file\n";

#our @EXPORT_OK = Package::Constants->list(__PACKAGE__); #https://www.perlmonks.org/?node_id=1072691; NOTE: "_OK" skips short/common names

#print STDERR scalar(@EXPORT_OK) . " consts exported:\n";
#foreach(@EXPORT_OK) { print STDERR "$_\n"; }
#my $val = main::thing("xyz");
#print STDERR "caller gave me $val\n";
#foreach my $arg (@ARGV) { print STDERR "arg $arg\n"; }

Download Details:

Author: swannman
Source Code: https://github.com/swannman/pdf2gerb

License: GPL-3.0 license

#perl 

Shardul Bhatt

Shardul Bhatt

1626775355

Why use Python for Software Development

No programming language is pretty much as diverse as Python. It enables building cutting edge applications effortlessly. Developers are as yet investigating the full capability of end-to-end Python development services in various areas. 

By areas, we mean FinTech, HealthTech, InsureTech, Cybersecurity, and that's just the beginning. These are New Economy areas, and Python has the ability to serve every one of them. The vast majority of them require massive computational abilities. Python's code is dynamic and powerful - equipped for taking care of the heavy traffic and substantial algorithmic capacities. 

Programming advancement is multidimensional today. Endeavor programming requires an intelligent application with AI and ML capacities. Shopper based applications require information examination to convey a superior client experience. Netflix, Trello, and Amazon are genuine instances of such applications. Python assists with building them effortlessly. 

5 Reasons to Utilize Python for Programming Web Apps 

Python can do such numerous things that developers can't discover enough reasons to admire it. Python application development isn't restricted to web and enterprise applications. It is exceptionally adaptable and superb for a wide range of uses.

Robust frameworks 

Python is known for its tools and frameworks. There's a structure for everything. Django is helpful for building web applications, venture applications, logical applications, and mathematical processing. Flask is another web improvement framework with no conditions. 

Web2Py, CherryPy, and Falcon offer incredible capabilities to customize Python development services. A large portion of them are open-source frameworks that allow quick turn of events. 

Simple to read and compose 

Python has an improved sentence structure - one that is like the English language. New engineers for Python can undoubtedly understand where they stand in the development process. The simplicity of composing allows quick application building. 

The motivation behind building Python, as said by its maker Guido Van Rossum, was to empower even beginner engineers to comprehend the programming language. The simple coding likewise permits developers to roll out speedy improvements without getting confused by pointless subtleties. 

Utilized by the best 

Alright - Python isn't simply one more programming language. It should have something, which is the reason the business giants use it. Furthermore, that too for different purposes. Developers at Google use Python to assemble framework organization systems, parallel information pusher, code audit, testing and QA, and substantially more. Netflix utilizes Python web development services for its recommendation algorithm and media player. 

Massive community support 

Python has a steadily developing community that offers enormous help. From amateurs to specialists, there's everybody. There are a lot of instructional exercises, documentation, and guides accessible for Python web development solutions. 

Today, numerous universities start with Python, adding to the quantity of individuals in the community. Frequently, Python designers team up on various tasks and help each other with algorithmic, utilitarian, and application critical thinking. 

Progressive applications 

Python is the greatest supporter of data science, Machine Learning, and Artificial Intelligence at any enterprise software development company. Its utilization cases in cutting edge applications are the most compelling motivation for its prosperity. Python is the second most well known tool after R for data analytics.

The simplicity of getting sorted out, overseeing, and visualizing information through unique libraries makes it ideal for data based applications. TensorFlow for neural networks and OpenCV for computer vision are two of Python's most well known use cases for Machine learning applications.

Summary

Thinking about the advances in programming and innovation, Python is a YES for an assorted scope of utilizations. Game development, web application development services, GUI advancement, ML and AI improvement, Enterprise and customer applications - every one of them uses Python to its full potential. 

The disadvantages of Python web improvement arrangements are regularly disregarded by developers and organizations because of the advantages it gives. They focus on quality over speed and performance over blunders. That is the reason it's a good idea to utilize Python for building the applications of the future.

#python development services #python development company #python app development #python development #python in web development #python software development

藤本  結衣

藤本 結衣

1636296420

線形検索のためのPythonプログラム

このチュートリアルでは、Pythonで線形検索プログラムを作成する方法を学習します。

まず、線形検索(シーケンシャル検索とも呼ばれます)は、リストまたは配列内の要素を見つけるために使用されます。一致するものが見つかるか、リスト全体が検索されるまで、リストの各要素を1つずつ/順番にチェックします。

線形探索アルゴリズム

以下の手順に従って線形検索を実装します。

  • ループを使用してリスト/配列をトラバースします。
  • すべての反復で、target 値をリスト/配列の指定された値に関連付け ます。
    • 値が一致する場合は、リスト/配列の現在のインデックスを返します。
    • それ以外の場合は、次の配列/リスト要素に移動します。
  • 一致するものが見つからない場合は、を返し -1ます。

線形検索のためのPythonプログラム

  • whileループを使用した線形検索用のPythonプログラム
  • Forループを使用した線形検索用のPythonプログラム
  • 再帰を使用したPythonプログラムでの線形検索

whileループを使用した線形検索用のPythonプログラム

# python program for linear search using while loop
 
#define list
lst = []
 
#take input list size
num = int(input("Enter size of list :- "))
 
for n in range(num):
    #append element in list/array
    numbers = int(input("Enter the array of %d element :- " %n))
    lst.append(numbers)
 
#take input number to be find in list   
x = int(input("Enter number to search in list :- "))
 
i = 0
flag = False
 
while i < len(lst):
    if lst[i] == x:
        flag = True
        break
  
    i = i + 1
  
if flag == 1:
    print('{} was found at index {}.'.format(x, i))
else:
    print('{} was not found.'.format(x))
    

プログラムの実行後、出力は次のようになります。

Enter size of list :-  5
Enter the array of 0 element :-  10
Enter the array of 1 element :-  23
Enter the array of 2 element :-  56
Enter the array of 3 element :-  89
Enter the array of 4 element :-  200
Enter number to search in list :-  89
89 was found at index 3.

Forループを使用した線形検索用のPythonプログラム

# python program for linear search using for loop
 
#define list
lst = []
 
#take input list size
num = int(input("Enter size of list :- "))
 
for n in range(num):
    #append element in list/array
    numbers = int(input("Enter the array of %d element :- " %n))
    lst.append(numbers)
 
#take input number to be find in list   
x = int(input("Enter number to search in list :- "))
 
i = 0
flag = False
 
for i in range(len(lst)):
    if lst[i] == x:
        flag = True
        break
  
if flag == 1:
    print('{} was found at index {}.'.format(x, i))
else:
    print('{} was not found.'.format(x))
    

プログラムの実行後、出力は次のようになります。

Enter size of list :-  6
Enter the array of 0 element :-  25
Enter the array of 1 element :-  50
Enter the array of 2 element :-  100
Enter the array of 3 element :-  200
Enter the array of 4 element :-  250
Enter the array of 5 element :-  650
Enter number to search in list :-  200
200 was found at index 3.

再帰を使用したPythonプログラムでの線形検索

# python program for linear search using for loop
 
#define list
lst = []
 
#take input list size
num = int(input("Enter size of list :- "))
 
for n in range(num):
    #append element in list/array
    numbers = int(input("Enter the array of %d element :- " %n))
    lst.append(numbers)
 
#take input number to be find in list   
x = int(input("Enter number to search in list :- "))
 
# Recursive function to linear search x in arr[l..r]  
def recLinearSearch( arr, l, r, x): 
    if r < l: 
        return -1
    if arr[l] == x: 
        return l 
    if arr[r] == x: 
        return r 
    return recLinearSearch(arr, l+1, r-1, x) 
     
 
res = recLinearSearch(lst, 0, len(lst)-1, x) 
  
if res != -1:
    print('{} was found at index {}.'.format(x, res))
else:
    print('{} was not found.'.format(x))
    

プログラムの実行後、出力は次のようになります。

Enter size of list :-  5
Enter the array of 0 element :-  14
Enter the array of 1 element :-  25
Enter the array of 2 element :-  63
Enter the array of 3 element :-  42
Enter the array of 4 element :-  78
Enter number to search in list :-  78
78 was found at index 4.

リンク: https://www.tutsmake.com/linear-search-in-python/

#python 

Lineare Suche in Python

In diesem Python-Beitrag erfahren Sie Folgendes:

  • Was ist eine lineare Suche?
  • Linearer Suchalgorithmus
  • Schreiben Sie ein Python-Programm für die lineare Suche mit While-Schleife
  • Schreiben Sie ein Python-Programm für die lineare Suche mit der For-Schleife
  • Lineare Suche im Python-Programm mit Rekursion

Was ist eine lineare Suche?

Eine lineare Suche, auch bekannt als sequentielle Suche, diese Methode wird verwendet, um ein Element innerhalb einer Liste oder eines Arrays zu finden. Es überprüft jedes Element der Liste nacheinander / sequentiell, bis eine Übereinstimmung gefunden wird oder die gesamte Liste durchsucht wurde.

Linearer Suchalgorithmus

Implementieren Sie die lineare Suche mit den folgenden Schritten:

  • Durchlaufen Sie die Liste/das Array mit einer Schleife.
  • Verknüpfen Sie in jeder Iteration den  target Wert mit dem angegebenen Wert der Liste/des Arrays.
    • Wenn die Werte übereinstimmen, geben Sie den aktuellen Index der Liste/des Arrays zurück.
    • Fahren Sie andernfalls mit dem nächsten Array-/Listenelement fort.
  • Wenn keine Übereinstimmung gefunden wird, geben Sie zurück  -1.

Schreiben Sie ein Python-Programm für die lineare Suche mit While-Schleife

# python program for linear search using while loop

#define list
lst = []

#take input list size
num = int(input("Enter size of list :- "))

for n in range(num):
    #append element in list/array
    numbers = int(input("Enter the array of %d element :- " %n))
    lst.append(numbers)

#take input number to be find in list   
x = int(input("Enter number to search in list :- "))

i = 0
flag = False

while i < len(lst):
	if lst[i] == x:
		flag = True
		break

	i = i + 1

if flag == 1:
	print('{} was found at index {}.'.format(x, i))
else:
	print('{} was not found.'.format(x))

Nach der Ausführung des Programms lautet die Ausgabe:

Enter size of list :-  5
Enter the array of 0 element :-  10
Enter the array of 1 element :-  23
Enter the array of 2 element :-  56
Enter the array of 3 element :-  89
Enter the array of 4 element :-  200
Enter number to search in list :-  89
89 was found at index 3.

Schreiben Sie ein Python-Programm für die lineare Suche mit der For-Schleife

# python program for linear search using for loop

#define list
lst = []

#take input list size
num = int(input("Enter size of list :- "))

for n in range(num):
    #append element in list/array
    numbers = int(input("Enter the array of %d element :- " %n))
    lst.append(numbers)

#take input number to be find in list   
x = int(input("Enter number to search in list :- "))

i = 0
flag = False

for i in range(len(lst)):
    if lst[i] == x:
        flag = True
        break

if flag == 1:
	print('{} was found at index {}.'.format(x, i))
else:
	print('{} was not found.'.format(x))

Nach der Ausführung des Programms lautet die Ausgabe:

Enter size of list :-  6
Enter the array of 0 element :-  25
Enter the array of 1 element :-  50
Enter the array of 2 element :-  100
Enter the array of 3 element :-  200
Enter the array of 4 element :-  250
Enter the array of 5 element :-  650
Enter number to search in list :-  200
200 was found at index 3.

Lineare Suche im Python-Programm mit Rekursion

# python program for linear search using for loop

#define list
lst = []

#take input list size
num = int(input("Enter size of list :- "))

for n in range(num):
    #append element in list/array
    numbers = int(input("Enter the array of %d element :- " %n))
    lst.append(numbers)

#take input number to be find in list   
x = int(input("Enter number to search in list :- "))

# Recursive function to linear search x in arr[l..r]  
def recLinearSearch( arr, l, r, x): 
    if r < l: 
        return -1
    if arr[l] == x: 
        return l 
    if arr[r] == x: 
        return r 
    return recLinearSearch(arr, l+1, r-1, x) 

res = recLinearSearch(lst, 0, len(lst)-1, x) 

if res != -1:
	print('{} was found at index {}.'.format(x, res))
else:
	print('{} was not found.'.format(x))

Nach der Ausführung des Programms lautet die Ausgabe:

Enter size of list :-  5
Enter the array of 0 element :-  14
Enter the array of 1 element :-  25
Enter the array of 2 element :-  63
Enter the array of 3 element :-  42
Enter the array of 4 element :-  78
Enter number to search in list :-  78
78 was found at index 4.