Perl array modifications with splice, split & join

In this article I'll demonstrate modifying array contents using splice, split & join functions.
I've worked with one dimensional arrays for the sake of simplicity but the concepts would be valid for multidimensional arrays as well.

1.) Splice function:

This is used to remove a defined number of elements from an array beginning with a given offset & replacing the elements with other elements if specified.
The syntax is as follows:

splice @ARRAY, OFFSET [ , LENGTH [ , LIST ] ]

This function will remove the elements of @ARRAY designated by OFFSET and LENGTH and replaces them with LIST, if specified.


2.) Split function:

The split function is used to convert a set of strings into an array or contents of a file into a multidimentional array.
The syntax is as follows:

split [ pattern [ , expression [ , LIMIT ] ] ]

This function splits a string into an array. If LIMIT is specified the function splits into at most that number of fields.
If PATTERN is omitted, splits on whitespace.
I use the split function a lot for splitting files into indivudal columns.


3.) The join function:

The join function is somewhat the opposite of the split function. Like the split function splits a string into an array using a specified delimeter, the join function combines individual array elements into a string.
This also proves useful if you are trying to change a delimeter of contents in a file.

The syntax for join function is as follows:

join expression, list

This function joins the separate strings of LIST into a single string with fields separated by the value of expression and returns the string.


Here is a short script demonstrating the use of the above discussed functions:

[root@cent6 ~]# cat af.pl
#!/usr/bin/perl -w

use strict ;

##using splice function##

my @array = qw/linux solaris unix aix hpux/ ;

print "OS names before splicing: @array \n" ;

splice (@array, 0, 2, "debian", "ubuntu") ;

print "OS names after  splicing: @array \n" ;

##using split function##

my $var = "linux:solaris:unix:hp-ux:tru64" ;

my @string = split (':', $var) ;

#print each element on new line: foreach (@string) { print "$_ \n" ; }
print "@string \n" ;

##using join function##

my $var1 = "linux,solaris,unix,hp-ux,tru64" ;

my @str = split /,/, $var1 ;

my $jn = join '|', @str ;
print "$jn \n" ;

[root@cent6 ~]#

On execution the code yields the following output:

[root@cent6 ~]# ./af.pl
OS names before splicing: linux solaris unix aix hpux
OS names after  splicing: debian ubuntu unix aix hpux
linux solaris unix hp-ux tru64
linux|solaris|unix|hp-ux|tru64
[root@cent6 ~]#


There are many more functions associated with arrays available like push, pop, shift, unshift & sort. I might write articles describing the other functions at a later date.