Simple Perl Examples

1)

#! /usr/bin/perl
@num = (3..5);
@alp = (a..e);
@mix = (3 .."s");
print "num == @num\n";
print "alp == @alp\n";
print "mix 3tos == @mix\n";
print " \@num[0] == @num[0]==== $num[0]=-==\n";
===== OUT PUT =======
 num == 3 4 5
 alp == a b c d e
 mix 3tos ==
 @num[0] == 3==== 3===
===== XXX =======


2)Simple add program using subroutine

use strict;
my @a = qw(1 2 3 4 5 6 7 8 9 );
my $c = myadd(@a);
print "sum = $c\n";

sub myadd {
    my $value=0;
    foreach my $num (@_) {
         $value += $num;
    }
    return($value);
}


3)

 use strict;
my $a = 2;
my $b = 3;
my $c = myadd($a,$b);
print "$a + $b = $c\n";

sub myadd {
    my ($num1, $num2) = @_;
    my $num3 = $num1 + $num2;
    return($num3);
}

4.  simple hash using key words keys & values

#! /usr/bin/perl
use strict;
my %hash = ("a" => "1",
            "b" => "2",
            "c" => "3",
              );
my @keys = sort keys %hash;
my @values = sort values %hash;
print " all keys of hash == @keys\n";
print " all values of hash == @values\n";
print "File name is == $0\n";

===== out put ======
 all keys of hash == a b c
 all values of hash == 1 2 3
 File name is == all_keys_values_function.pl
 ===== XXX =====

5) using $# syntax

#! /usr/bin/perl
use strict;
my @ary = qw(hi shaik shabbir);
my $scalar = scalar(@ary);
print "\$scalar == $scalar\n";
my $last_ary_value = $#ary;
print "\$last_ary_value == $last_ary_value\n";
$#ary++;
@ary[$#ary] = "suresh";
print "\$#ary == $#ary\n";
print "@ary == @ary\n";
print "\n";

===== out put ======
$scalar == 3
$last_ary_value == 2
$#ary == 3
hi shaik shabbir suresh == hi shaik shabbir suresh

 ===== XXX =====


6) concatenation operator "."

#! /usr/bin/perl
use strict;
my $name1 = 5; #"Shaik";
my $name2 = 4; #"Shabbir" ;
my $full_name = $name1.$name2;
print "full name == $full_name\n";

===== out put ======
full name == 54
===== XXX =====



7)  keword each in Hashes
 
 #! usr/bin/perl
use strict;

my %hash = ("a" => "1",
            "b" => "2",
            "c" => "3",
              );

my $key;
my $value;

for (my $i = 0; $i <= 10; $i++) {
     ($key,$value) = each %hash;
    print "key == $key and value == $value\n";
}
===== out put ======
key == c and value == 3
key == a and value == 1
key == b and value == 2
key ==  and value ==
key == c and value == 3
key == a and value == 1
key == b and value == 2
key ==  and value ==
key == c and value == 3
key == a and value == 1
key == b and value == 2
===== XXX =====

8)  finding even and odd numbers
 #! /usr/bin/perl
use strict;
my @number = (2 .. 100);
my ($even,$odd) = (0,0);
my (@even_num,@odd_num);

foreach my $num(@number){
    my $check = $num % 2;
    if(!$check){
       $even_num[$even] = $num;
        $even++;
     }
    else{
        $odd_num[$odd] = $num;
        $odd++;
     }
}
print "Even numbers are == @even_num\n";
print "Odd Numbers are == @odd_num\n\n";
print "Total Even numbers are == $even\n";
print "Total Odd Numbers are == $odd\n";

9) shift and unshift syntax

#! /usr/bin/perl -w
use strict;
my @ary = "1";
print "0 == $ary[0]\n";
unshift(@ary,"2");
print "unshift 0 = $ary[0] 1 == $ary[1]\n";
my $pop = shift(@ary);
print "shift == @ary\n";

10) Comparing Arrays and Hashes

use strict;

my @my_array = ("e0",
                "e1",
                "e2");

my %my_hash = ("key0" => "value0",
               "key1" => "value1",
               "key2" => "value2",);


 print "ARRAY: $my_array[0]\n"; #=== > array print syntax
 print "HASH: $my_hash{\"key0\"}\n"; #=== > Hash print syntax


foreach my $element (@my_array) {
    print "$element\n";
}

print "\n\n";

foreach my $xyz (keys %my_hash) {
    print "$xyz: $my_hash{$xyz}\n";
}

11) Hash Dumper syntax && Hash print using hash reference

#! /usr/bin/perl
use strict;
use Data::Dumper;

my %hash = ("a" => "1",
            "a_hash" => {"a1" => "a1_value",
                         "a2" => "a2_value",
                        },
            "b" => "2",
            "c_hash" => {"c1" => "c1_value",
                         "c2" => "c2_value",
                        },
            );
my %hash_1 = ("a_hash1" => "1",
            "a_hash1" => {"a1_hash1" => "a1_value_hash1",
                          "a2_hash1" => "a2_value_hash1",
                        },
            "b_hash1" => "2",
            "c_hash1" => {"c1_hash1" => "c1_value_hash1",
                          "c2_hash1" => "c2_value_hash1",
                        },
            );
my %hash_2 = ("a_hash2" => "1",
            "a_hash2" => {"a1_hash2" => "a1_value_hash2",
                          "a2_hash2" => "a2_value_hash2",
                        },
            "b_hash2" => "2",
            "c_hash2" => {"c1_hash2" => "c1_value_hash2",
                         "c2_hash2" => "c2_value_hash2",
                        },
            );

my @hash_ref = (\%hash,\%hash_1,\%hash_2);
print Dumper(@hash_ref);
print "=====Printing using Hash Reference======\n";
print "$hash_ref[0]->{a_hash}{a1}\n";





12) Hierarchical Hashes Syntax

#! /usr/bin/perl
use strict;

my %simple_hash = ("a" => "1",
                   "b" => "2",);
my %hierarchical_hash = ("c" => {
                                 "c1" => "c1_value",
                                 "c2" => "c2_value",
                                },
                         "d" => {"d1" => "d1_value",
                                 "d2" => "d2_value",
                                },
                        );
my @simple_keys = keys %simple_hash;
my @hirerchy_keys = keys %hierarchical_hash;

print "simple_keys ==> @simple_keys\n";
print "value of simple_keys ==> $simple_hash{$simple_keys[0]}\n\n";
print "hirerchy_keys ==> @hirerchy_keys\n";
print "Value of hirerchy_keys ==> $hierarchical_hash{$hirerchy_keys[0]}{c1}\n";

my $value = $hierarchical_hash{c}->{c1};
print "===Value == $value\n";





======= OUT PUT ===
 simple_keys ==> a b
value of simple_keys ==> 1
hirerchy_keys ==> c d
Value of hirerchy_keys ==> c1_value
===Value == c1_value
=== XXX ===


13) Interview question to enter name and get its game (imc.pl)

#! /usr/bin/perl
use strict;
use Data::Dumper;

my @ary_string = ();
my %hash;
my %hash_of_hash;
$ary_string[0] = ("shaik is playing cricket");
$ary_string[1] = ("shabbir is playing footboll");
#print "@ary_string\n";
foreach(@ary_string) {
  $_ =~ m/^(.*) is playing (.*)$/i ;
  #print "\$1 === $1 \$2 == $2\n";
  $hash_of_hash{$1}->{$1} = ($1 => $2);
  $hash{$1} = ($1 => $2);
}
print Dumper(%hash);
print "\n\n";
print Dumper(%hash_of_hash);
print "Enter the name and get game\n";
my $name = <stdin>;
chomp($name);
print "from hash == $name is playing $hash{$name}\n\n";
print "from hash_of_hash == $name is playing $hash_of_hash{$name}->{$name}\n\n";

What Beginners should know about Perl...?

Hi all,

      Perl is a versatile language and Before starting perl be prepared with a mind set that Perl is a very wisely used for scripting and easy to understand. Perl Scripting skills will help you to understand any other languages in a faster way. Intern it will boost your confidence with coding and understanding skill sets...... 

    So lets Your coding skill begin with Perl.........

1. How to access data?
    1.1:  Accept input data Store it Process it.
    1.2:  Store data internally and process it.
2. Most important Storage elements
    2.1: Array
    2.2: Hash
3. Accessing Hash
    3.1: Hash Keys
    3.2: Hash Values
    3.3: Hash Reference
4. Creacting and Accessing Sub modules
5. Pattern matching
6. Buit in Varilables
    6.1: $0,$1,$2 and so on
    6.2: $_, ".", $/
7. Creating your own Perl Module and making use of it.

"Above mentioned are the most important and customised contenets that enhance your confident to clear almost any interview on perl with confident"...