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Articles by Mohd Mohtashim
Page 5 of 19
Multiline Strings in Perl
If you want to introduce multiline strings into your programs, you can use the standard single quotes as below −Example#!/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#!/usr/bin/perl print
Read MoreV-Strings in Perl
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#!/usr/bin/perl $smile = v9786; $foo = v102.111.111; $martin = v77.97.114.116.105.110; print "smile = $smile"; print "foo = $foo"; print "martin = $martin";OutputThis will also produce the same result −smile = ☺ foo = foo martin = ...
Read MorePerl Special Literals
Let me tell you about three special literals __FILE__, __LINE__, and __PACKAGE__ represent the current filename, line number, and package name at that point in your program.They may be used only as separate tokens and will not be interpolated into strings. Check the below example −Example#!/usr/bin/perl print "File name ". __FILE__ . ""; print "Line Number " . __LINE__ .""; print "Package " . __PACKAGE__ .""; # they can not be interpolated print "__FILE__ __LINE__ __PACKAGE__";OutputThis will produce the following result −File name hello.pl Line Number 4 Package main __FILE__ __LINE__ __PACKAGE__
Read MoreAccessing Array Elements in Perl
When accessing individual elements from an array in Perl, you must prefix the variable with a dollar sign ($) and then append the element index within the square brackets after the name of the variable. For example −Example#!/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 the ...
Read MorePerl Sequential Number Arrays
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#!/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
Read MoreArray Size in Perl
The size of an array in Perl can be determined using the scalar context on the array - the returned value will be the number of elements in the array −@array = (1, 2, 3); print "Size: ", scalar @array, "";The value returned will always be the physical size of the array, not the number of valid elements. You can demonstrate this, and the difference between scalar @array and $#array, using this fragment is as follows −Example#!/usr/bin/perl @array = (1, 2, 3); $array[50] = 4; $size = @array; $max_index = $#array; print "Size: $size"; print "Max Index: $max_index";OutputThis will ...
Read MoreAdding and Removing Elements in Perl Array
Perl provides a number of useful functions to add and remove elements in an array. You may have a question what is a function? So far you have used the print function to print various values. Similarly, there are various other functions or sometimes called subroutines, which can be used for various other functionalities.Sr.No.Types & Description1push @ARRAY, LISTPushes the values of the list onto the end of the array.2pop @ARRAYPops off and returns the last value of the array.3shift @ARRAYShifts the first value of the array off and returns it, shortening the array by 1 and moving everything down.4unshift @ARRAY, ...
Read MoreSlicing Array Elements in Perl
You can also extract a "slice" from an array - that is, you can select more than one item from an array in order to produce another array.Example#!/usr/bin/perl @days = qw/Mon Tue Wed Thu Fri Sat Sun/; @weekdays = @days[3, 4, 5]; print "@weekdays";OutputThis will produce the following result −Thu Fri SatThe specification for a slice must have a list of valid indices, either positive or negative, each separated by a comma. For speed, you can also use the .. range operator −Example#!/usr/bin/perl @days = qw/Mon Tue Wed Thu Fri Sat Sun/; @weekdays = @days[3..5]; print "@weekdays";OutputThis will produce the ...
Read MoreReplacing Array Elements in Perl
Now we are going to introduce one more function called splice(), which has the following syntax −Syntaxsplice @ARRAY, OFFSET [ , LENGTH [ , LIST ] ]This function will remove the elements of @ARRAY designated by OFFSET and LENGTH, and replaces them with LIST if specified. Finally, it returns the elements removed from the array. Following is the example −Example#!/usr/bin/perl @nums = (1..20); print "Before - @nums"; splice(@nums, 5, 5, 21..25); print "After - @nums";OutputThis will produce the following result −Before - 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 ...
Read MoreTransform Perl Arrays to Strings
We can use the join() function in Perl to rejoin the array elements and form one long scalar string. This function has the following syntax −Syntaxjoin EXPR, LISTThis function joins the separate strings of LIST into a single string with fields separated by the value of EXPR and returns the string. Following is the example −Example#!/usr/bin/perl # define Strings $var_string = "Rain-Drops-On-Roses-And-Whiskers-On-Kittens"; $var_names = "Larry, David, Roger, Ken, Michael, Tom"; # transform above strings into arrays. @string = split('-', $var_string); @names = split(', ', $var_names); $string1 = join( '-', @string ); $string2 = join( ', ', @names ); ...
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