Scalars: also called variables

$i = 10;
$string = ‘Ramraj’;
$float = 1.005;
print “Int value is = $i n”;
print “String value is = $string n”;
print “Float value is = $float n”;

In above code snippet three variables or scalars are defined, and the first one $i  stores integer values, $string stores string value, and $float scalar is floating point value. Perl scalars can hold integers or numbers, string values, and decimal point values such as float, double etc. there is no need to define variable type unlike in java, C, and C++.  Perl is dynamic language and perl interpreter determines types automatically at runtime, this is one big benefit compare to those languages.

In the above code, three print statements prints the all three variables, and ‘n’ is new line character to print each line in a new line.

Arrays: List of scalars

Arrays are defined with prefixed ‘@’  symbol, which is called at symbol. Arrays store list of elements or scalars and provides mechanism to retrieve the values from the array. Arrays are very important and fundamental data structure for any programming languages.

array syntax:

@array = (1, 2, 3, 4, 5);  #list of integer values
@strarray = (‘ram’, ‘raj’, ‘jhon’, ‘mohan’);  #list of string values
print “List the integer array: @array n”
print “List the string array: @strarray n”
print “Print the first value: $array[0]“

Arrays are zero index based list means first values stores at zero index, and next value at 1st index and so on. Above you can see two arrays one with a list of integer values, and another array filled with string values. To print array values use index value with array scalar like $array[0] prints ‘1′ , and $array[1] print ‘2′.

Hashes: also called Dictionaries

Hashes are prefixed with ‘%’ symbol and defines name value pair mappings.

hashes syntax:

%ha = (“Ram” => 1, “Raj” => 2, “Bem” => 9, “hey” => 10);

print $ha{“Ram”} #prints value ‘1′

We have now learned the basic data element structures and syntax in perl. Try yourself all above mentioned code samples and let me know if you have any problem in understanding.

1. Install perl distribution from perl.org, download here

or

you can also downalod perl from activestate.com which comes few additional perl modules.

2. To write perl programs you need a text editor or perl IDE. you can use simple notepad or textpad, or you can also perl IDE such as a Open Perl IDE or Perl Express. I personally use advance notepad called NotePad++, which is opensource and free software.

3.  Now, create a file called testperl.pl, perls files end with .pl file extension.

4. Write the below statement in the created testperl.pl file

print “Hello World n”;

5. Open the command prompt, and go to the folder where you have a testperl.pl and run the below command

perl testperl.pl

6. Bravo! now you could see “Hello World” on command prompt console.