Perl/Basics/Variables and Data Types/Arrays/Helper Functions

join()

Join will compile an array into a scalar. Using the array example above, @messages, the following code will generate the string "Hello world!\n, I like perl!\n" as a scalar:

<syntaxhighlight lang="perl">my @messages = ("Hello world!\n","I like perl!\n"); my $joined_message = join(", ",@messages); print $joined_message;</syntaxhighlight>

split()

Split takes a scalar and converts it to an array using a delimiter. Using our string from earlier:

<syntaxhighlight lang="perl">my $joined_message = "Hello world!\n, I like perl!\n"; my @messages = split('/, /',$joined_message); print $messages[0]; print $messages[1]; print "Size of messages array: ". $#messages . "\n";</syntaxhighlight>

push()

The push() function is used to append an element or elements to the end of an array, similar to the push instruction in assembly and treats the array like a stack.

my @array; push(@array,'element one'); push(@array,('element two','element three'));

You can also add to the end of an array with:

$array[$#array] = "new element";

pop()

The pop() function is similar to the pop instruction in assembly and treats the array like a stack.

my @array; $array[$#array] = 1; $popped = pop(@array);

The same affect can be acheived with:

$popped = $array[$#array--];

Executing pop() on an array will delete the highest order array element.

unshift()

The unshift() function is like the inverse of the push() function and treats the array like a stack. In stead of pushing to the top of the stack, this function operates against the bottom of the stack.

my @array; $array[0] = 1; unshift(@array,0); # $array[0] now contains "0" and $array[1] now contains [1].

shift()

The shift() function is like the inverse of the pop() function and treats the array like a stack. In stead of popping from the top of the stack, this function operates against the bottom of the stack.

my @array = (0,1); my $first_element = shift(@array); # $array[0] now contains one, and @array only contains one element

Warning: Executing shift() on an array will delete the lowest order array element, changing the index of all elements.