Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Perl offers a shortcut for sequential numbers and letters. Rather than typing out each element when counting to 100 for example, we can do something like as follows −Example Live Demo#!/usr/bin/perl @var_10 = (1..10); @var_20 = (10..20); @var_abc = (a..z); print "@var_10"; # Prints number from 1 to 10 print "@var_20"; # Prints number from 10 to 20 print "@var_abc"; # Prints number from a to zHere double dot (..) is called range operator. This will produce the following result −1 2 3 4 5 6 7 8 9 10 10 11 12 13 14 15 16 17 18 19 20 a b c d e f g h i j k l m n o p q r s t u v w x y z
When accessing individual elements from an array in Perl, you must prefix the variable with a dollar sign ($) and then append the element index within the square brackets after the name of the variable. For example −Example Live Demo#!/usr/bin/perl @days = qw/Mon Tue Wed Thu Fri Sat Sun/; print "$days[0]"; print "$days[1]"; print "$days[2]"; print "$days[6]"; print "$days[-1]"; print "$days[-7]";OutputThis will produce the following result −Mon Tue Wed Sun Sun MonArray indices start from zero, so to access the first element you need to give 0 as indices. You can also give a negative index, in which case you select ... Read More
Perl Array variables are prefixed with the @ sign and are populated using either parentheses or the qw operator. For example −@array = (1, 2, 'Hello'); @array = qw/This is an array/;The second line uses the qw// operator, which returns a list of strings, separating the delimited string by white space. In this example, this leads to a four-element array; the first element is 'this' and last (fourth) is 'array'. This means that you can use different lines as follows −@days = qw/Monday Tuesday ... Sunday/;You can also populate an array by assigning each value individually as follows −$array[0] = 'Monday'; ... $array[6] = 'Sunday';
Let me tell you about three special literals __FILE__, __LINE__, and __PACKAGE__ represent the current filename, line number, and package name at that point in your program.They may be used only as separate tokens and will not be interpolated into strings. Check the below example −Example Live Demo#!/usr/bin/perl print "File name ". __FILE__ . ""; print "Line Number " . __LINE__ .""; print "Package " . __PACKAGE__ .""; # they can not be interpolated print "__FILE__ __LINE__ __PACKAGE__";OutputThis will produce the following result −File name hello.pl Line Number 4 Package main __FILE__ __LINE__ __PACKAGE__
A literal of the form v1.20.300.4000 is parsed as a string composed of characters with the specified ordinals. This form is known as v-strings.A v-string provides an alternative and more readable way to construct strings, rather than use the somewhat less readable interpolation form "\x{1}\x{14}\x{12c}\x{fa0}".They are any literal that begins with a v and is followed by one or more dot-separated elements. For example −Example Live Demo#!/usr/bin/perl $smile = v9786; $foo = v102.111.111; $martin = v77.97.114.116.105.110; print "smile = $smile"; print "foo = $foo"; print "martin = $martin";OutputThis will also produce the same result −smile = ☺ foo = foo martin ... Read More
If you want to introduce multiline strings into your programs, you can use the standard single quotes as below −Example Live Demo#!/usr/bin/perl $string = 'This is a multiline string'; print "$string";OutputThis will produce the following result −This is a multiline stringYou can use "here" document syntax as well to store or print multiline as below −Example Live Demo#!/usr/bin/perl print
The following example demonstrates the usage of various types of string scalars. Notice the difference between single-quoted strings and double-quoted strings −Example Live Demo#!/usr/bin/perl $var = "This is string scalar!"; $quote = 'I m inside single quote - $var'; $double = "This is inside single quote - $var"; $escape = "This example of escape -\tHello, World!"; print "var = $var"; print "quote = $quote"; print "double = $double"; print "escape = $escape";OutputThis will produce the following result −var = This is string scalar! quote = I m inside single quote - $var double = This is inside single quote - ... Read More
A scalar is most often either a number or a string. Following example demonstrates the usage of various types of numeric scalars −Example Live Demo#!/usr/bin/perl $integer = 200; $negative = -300; $floating = 200.340; $bigfloat = -1.2E-23; # 377 octal, same as 255 decimal $octal = 0377; # FF hex, also 255 decimal $hexa = 0xff; print "integer = $integer"; print "negative = $negative"; print "floating = $floating"; print "bigfloat = $bigfloat"; print "octal = $octal"; print "hexa = $hexa";OutputThis will produce the following result −integer = 200 negative = -300 floating = 200.34 bigfloat = -1.2e-23 octal = 255 hexa = 255
Perl treats the same variable differently based on Context, i.e., the situation where a variable is being used. Let's check the following example −Example Live Demo#!/usr/bin/perl @names = ('John Paul', 'Lisa', 'Kumar'); @copy = @names; $size = @names; print "Given names are : @copy"; print "Number of names are : $size";OutputThis will produce the following result −Given names are : John Paul Lisa Kumar Number of names are : 3Here @names is an array, which has been used in two different contexts. First, we copied it into another array, i.e., list, so it returned all the elements assuming that context ... Read More
A hash is a set of key/value pairs. Hash variables are preceded by a percent (%) sign. To refer to a single element of a hash, you will use the hash variable name followed by the "key" associated with the value in curly brackets.Here is a simple example of using hash variables −Example Live Demo#!/usr/bin/perl %data = ('John Paul', 45, 'Lisa', 30, 'Kumar', 40); print "\$data{'John Paul'} = $data{'John Paul'}"; print "\$data{'Lisa'} = $data{'Lisa'}"; print "\$data{'Kumar'} = $data{'Kumar'}";OutputThis will produce the following result −$data{'John Paul'} = 45 $data{'Lisa'} = 30 $data{'Kumar'} = 40