Programming Scripts Articles - Page 15 of 37

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';

A Perl array is a variable that stores an ordered list of scalar values. Array variables are preceded by an "at" (@) sign. To refer to a single element of an array, you will use the dollar sign ($) with the variable name followed by the index of the element in square brackets.ExampleHere is a simple example of using the array variables − Live Demo#!/usr/bin/perl @ages = (25, 30, 40); @names = ("John Paul", "Lisa", "Kumar"); print "\$ages[0] = $ages[0]"; print "\$ages[1] = $ages[1]"; print "\$ages[2] = $ages[2]"; print "\$names[0] = $names[0]"; print "\$names[1] = $names[1]"; print "\$names[2] = $names[2]";Here we ... Read More

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

A scalar is a single unit of data. That data might be an integer number, floating-point, a character, a string, a paragraph, or an entire web page.Here is a simple example of using scalar variables −Example Live Demo#!/usr/bin/perl $age = 25;                # An integer assignment $name = "John Paul";      # A string $salary = 1445.50;        # A floating point print "Age = $age"; print "Name = $name"; print "Salary = $salary";OutputThis will produce the following result −Age = 25 Name = John Paul Salary = 1445.5