Scalar

Scalar : 

In Perl, scalar can store a single value at any time.
In the following example, $str contains a string value.
We can store any single integer, string, float value in a scalar. It's as simple as that.

E.g., $str1 = 100;
        $str2 = 'test';
        $str3 = 300.2;

use strict;
use warnings;
use Data::Dumper;

#In Perl, scalar can store a single value at any time.
#In the following example, $str contains a string value.
#We can store any single integer, string, float value in a scalar. It's as simple as that.


#Integer
my $num = 300;
print "\n Number : " . $num;

#String
my $str = "Alex Perter John Dane";

#Array
my @arr = split(/ /,$str);

print "\n After Split : " . Dumper(\@arr);
  

Output:

 Number : 300
 After Split : $VAR1 = [
          'Alex',
          'Perter',
          'John',
          'Dane'
        ];

Please refer to other topics in Perl like :
How to read command line arguments in Perl
How to pass command line arguments to perl script
Loop through Directory and read the files in Perl
How to create excel report in Perl

Please refer to other topics on Unix like :
Unix Delete Duplicated Lines in a File
Unix Unique Lines in a File
Unix Grep Examples
Unix Cut Command Examples
Search a Directory in Unix
Unix For Loop
pushd & popd in Unix
Find Size of Directory
Word Count

Please refer to other topics on AWK like :
Awk Examples
Print First Two Columns of File
Print Last Two Columns of File

Please refer to other topics on Dict like :
Dict in Python
Dict keys and values in Python

Please refer to other topics on List like :
List in Python
Append to list in Python
Delete the last name from the list in Python
Remove an element from List in Python
Check an element exists in an list in Python
Python Filter Vs Map Vs List Comprehension

Please refer to other topics on File Concepts like :
Print File Content in Python
Print File in Reverse Order in Python

Please refer to Regular Expressions Concepts :
Brief on Regular Expressions
Greedy Operators in Regular Expressions in Perl
Modifiers in Regular Expressions in Perl
Capturing concept in Regular Expressions in Perl
Capture Pre Match ,Post Match, Exact match in Regular Expressions in Perl
Non Capturing Paranthesis in Regular Expressions in Perl
Substitute nth occurance in Regular Expressions in Perl
All Topics in Regular Expressions in Perl

You might also wish to read other topics on Python like :
Python Class and Object Example
Inheritance in Python
Packages in Python
Exceptions in Python
How to remove duplicate lines from a file in Perl
How to remove duplicate lines from a file in Pyhton

map

1)
$str = "2-5,3-9,1-2,8-1,4-7,5-9,20-3,16-9";
@array=split(/,/, $str);
my @a1= (map
{
($left,$right)=split(/-/,$_);
$left*$right;
}
@array
);
print join(",",@a1),"\n";

2)
@array = (20, 3, 1, 9, 100, 88, 75);
my @new_array = (map { $_*2; } @array);
print join(",", @new_array), "\n";

reverse keyword

#!F:\Perl\bin\perl -w
use strict;

my $a=9;
print "Before Reverse:\n", (1..$a);
print "\nAfter Reverse:\n", reverse (1 .. $a);

' tr ' or ' y '

Removing the duplicate characters from the string:

#!F:\Perl\bin\perl -w
use strict;


#Removing the duplicate characters ('c' , 'd') but not ('e') from the string
my $val = 'abcccdddddeeeeeeeeeeeeecccccc';
print "\n Given String:", $val;

$val =~ y/cd//s; # 'y' is nothing but 'tr'

print "\nAfter :$val\n";

substitute for n'th occurance

#!F:\Perl\bin\perl -w
use strict;

# Substitue 3rd occurance of 'perl' with 'PERL'
my $text = 'perl is good, perl is better, perl is best';
print "\n INPUT Text:", $text;

my $nth_occurance = 3;
my $count=0;

$text =~ s{(perl)}{
++$count == $nth_occurance ? 'PERL' : $1
}ige;

print "\n OUTPUT Text:", $text,"\n";

Sort an Array

1) For number Array

#!F:\Perl\bin\perl -w
use Data::Dumper;

my @array = (20,10,50,40,30); #Unsorted Number Array
print "\n Unsorted Array is: @array";
my @sorted = sort { $a <=> $b } @array;

# '<=>' for numbers only# 'cmp' used for numbers as well as strings
print "\n sorted Array is: @sorted";
my @sorted = sort { $a cmp $b } @array;

print "\n sorted Array is: @sorted";


2) For String Array

#!F:\Perl\bin\perl -w
use Data::Dumper;#Unsorted String Array
my @array = qw/sandhya eswar prabhath vamsi/;
print "\n Unsorted Array is: @array";

my @sorted = sort { $a cmp $b } @array;

# 'cmp' can be used for both strings as well as numbers
print "\n sorted Array is: @sorted";

use of $_

#!F:\Perl\bin\perl -w
use strict;

1) print "\n", $_ for (1..10);

2)
my %hash = ( a => 100, b => 200, c => 300);
print "\n", $_ for keys(%hash);:

How to use Ciel and Floor Functions

#!F:\Perl\bin\perl -w
use strict;

use POSIX; #ciel and floor available in POSIX module

$a = ceil(3.45);
print "\n $a"; #gives o/p as '4'

$b = floor(3.45);
print "\n $b"; #gives o/p as '3'

printf("\n%.3f", 3.1415926535); #gives output as 3.142, rounds of to 3 digits
#For Rounding use printf and sprintf