Perl Arrays

@array = (1,2,3);
print "Size: ",scalar @array,"\n";

#!/usr/bin/perl

@ages = (25, 30, 40);             
@names = ("John Paul", "Lisa", "Kumar");

print "\$ages[0] = $ages[0]\n";
print "\$ages[1] = $ages[1]\n";
print "\$ages[2] = $ages[2]\n";
print "\$names[0] = $names[0]\n";
print "\$names[1] = $names[1]\n";
print "\$names[2] = $names[2]\n";

						
Array Creation

@array = (1, 2, 'Hello');
@array = qw/This is an array/;

						

@days = qw/Monday
Tuesday
...
Sunday/;

						

$array[0] = 'Monday';
...
$array[6] = 'Sunday';

						
Accessing Array Elements

#!/usr/bin/perl

@days = qw/Mon Tue Wed Thu Fri Sat Sun/;

print "$days[0]\n";
print "$days[1]\n";
print "$days[2]\n";
print "$days[6]\n";
print "$days[-1]\n";
print "$days[-7]\n";

						

print $days[-1]; # outputs Sun
print $days[-7]; # outputs Mon

						
Sequential Number Arrays

#!/usr/bin/perl

@var_10 = (1..10);
@var_20 = (10..20);
@var_abc = (a..z);

print "@var_10\n";   # Prints number from 1 to 10
print "@var_20\n";   # Prints number from 10 to 20
print "@var_abc\n";  # Prints number from a to z

						
Array Size

#!/uer/bin/perl

@array = (1,2,3);
$array[50] = 4;

$size = @array;
$max_index = $#array;

print "Size:  $size\n";
print "Max Index: $max_index\n";

						
Adding and Removing Elements in Array

#!/usr/bin/perl

# create a simple array
@coins = ("Quarter","Dime","Nickel");
print "1. \@coins  = @coins\n";

# add one element at the end of the array
push(@coins, "Penny");
print "2. \@coins  = @coins\n";

# add one element at the beginning of the array
unshift(@coins, "Dollar");
print "3. \@coins  = @coins\n";

# remove one element from the last of the array.
pop(@coins);
print "4. \@coins  = @coins\n";

# remove one element from the beginning of the array.
shift(@coins);
print "5. \@coins  = @coins\n";

						
Slicing Array Elements

#!/usr/bin/perl

@days = qw/Mon Tue Wed Thu Fri Sat Sun/;

@weekdays = @days[3,4,5];

print "@weekdays\n";

						

#!/usr/bin/perl

@days = qw/Mon Tue Wed Thu Fri Sat Sun/;

@weekdays = @days[3..5];

print "@weekdays\n";

						
Replacing Array Elements

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

						

#!/usr/bin/perl

@nums = (1..20);
print "Before - @nums\n";

splice(@nums, 5, 5, 21..25); 
print "After - @nums\n";

						
Transform Strings to Arrays

split [ PATTERN [ , EXPR [ , LIMIT ] ] ]

						

#!/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);

print "$string[3]\n";  # This will print Roses
print "$names[4]\n";   # This will print Michael

						
Transform Arrays to Strings

join EXPR, LIST

						

#!/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 );

print "$string1\n";
print "$string2\n";

						
Sorting Arrays

sort [ SUBROUTINE ] LIST

						

#!/usr/bin/perl

# define an array
@foods = qw(pizza steak chicken burgers);
print "Before: @foods\n";

# sort this array
@foods = sort(@foods);
print "After: @foods\n";

						
The $[ Special Variable

#!/usr/bin/perl

# define an array
@foods = qw(pizza steak chicken burgers);
print "Foods: @foods\n";

# Let's reset first index of all the arrays.
$[ = 1;

print "Food at \@foods[1]: $foods[1]\n";
print "Food at \@foods[2]: $foods[2]\n";

						
Merging Arrays

#!/usr/bin/perl

@numbers = (1,3,(4,5,6));

print "numbers = @numbers\n";

						

#!/usr/bin/perl

@odd = (1,3,5);
@even = (2, 4, 6);

@numbers = (@odd, @even);

print "numbers = @numbers\n";

						
Selecting Elements from Lists

#!/usr/bin/perl

$var = (5,4,3,2,1)[4];

print "value of var = $var\n"

						

#!/usr/bin/perl

@list = (5,4,3,2,1)[1..3];

print "Value of list = @list\n";