perl array operations

Declaring an empty array

my @arr = ();

Adding elements in an array 

push( @arr , "hello" ); # directly putting value
my $element = "world";
push( @arr ,  $element ); # putting variable

Printing elements of array 

foreach my $value(@arr) {
     print "$value\n";
}

Passing array as argument in a function
There are two ways to pass a data structure to subroutine/function in perl :

• Pass by value :

sub printing {
  my @array = @_; # @_ means retrieve all the passed arguments 
  print "priting content of array\n";
  foreach my $value(@array) {
    print "$value\n";
  }
}

printing @arr; # function call

but with this method, you can't change content of array e.g. you may want to add elements in array in subroutine/function.

• Pass by reference :

sub add {
  my $ref = shift(); # get the first argument
  my $element = shift(); # get the second argument
  push(@$ref,$element);
}
add(\@arr,"Hi"); #\@arr represents reference to arr

you can copy paste the following program in a file (that consist of all of above statements) and try with perl interpreter :

use strict;
use warnings;

sub add {
  my $ref = shift();
  my $element = shift();
  push(@$ref,$element);
}
sub printing {
  my @array = @_;
  print "priting content of array\n";
  foreach my $value(@array) {
    print "$value\n";
  }
}
my @arr = ();
push(@arr,"Hello");
my $w = "world";
push(@arr,$w);
foreach my $value(@arr) {
  print "$value\n";
}
printing @arr;
add(\@arr,"Hii");
printing @arr;