PERL Interview Questions for VLSI Jobs : Part 2

In this article, we explored key concepts in PERL programming. We began with interpolation, discussing its significance and practical applications, followed by the benefits of using the strict module for code integrity. We compared the chop and chomp functions with examples, examined string manipulation by contrasting concatenate and join, and clarified the differences between use and require directives. Additionally, we demonstrated how to localize variables to manage scope and explained reading a file directly into an array for efficient file handling. This article provides practical insights into mastering PERL fundamentals.

1. What is interpolation in PERL ?

Double-quoted strings are “interpolated” : any variable names found inside the string will be replaced by their value. 

Example : 

2. Why we use strict module ?
Or
Why  “use strict” is a Must while using PERL Data Structures ?

Here is our PERL Code :

When we execute the code we get the below error message due to use of the STRICT Module :
Execution of ./accident.pl aborted due to compilation errors.
As a Corrective Action , Change  the print command to : print $aref->[2][2]

Global symbol "@aref" requires explicit package name (did you forget to declare "my @aref"?) at ./accident.pl line 9.

3. Tell/Show the  Difference between Chop and Chomp :

The chomp() function removes ONLY new line character from the end of the string. 
WHEREAS
The Perl chop() function removes last character from a string regardless of what that character is. 
Let us see the example below :

Produces the below output :

=======Mary Had a Little Lamb=============
=======Mary Had a Little Lamb=============
=======Mary Had a Little Lamb =============
=======Mary Had a Little Lamb=============
=======Mary Had a Little Lamb Once=============
=======Mary Had a Little Lamb Onc=============

Now you can spot the difference ..... or else watch the video well below this page.

4. Tell/Show The Difference between Concat & Join  :

• Concat & Join both are used to stitch more than one strings together.

• Concat is used in very straight forward & its a binary operator.

• Join is a PERL function to join contents of a list/array.

Here goes our example to show the difference:

The output is :

 Happy Birthday
 Happy Morning 

Now you can spot the difference ..... or else watch the video well below this page.

5. How to local-ise a variable ?

This below example will help you to do that :

Which gives the output :

 Num=100 @ outside 
 Num=10 A
 Num=10 Quick
 Num=10 Brown
 Num=10 Fox

Watch the video well below this page for explanation.

6. How to read a file directly in to an array ?

Our input file contains : 
A quick 
Brown fox
Jumped Over
A Lazy
White Dog

Which we are reading through the below PERL Code:

Which gives output of the file being read:

$VAR1 = [
          'A quick ',
          'Brown fox',
          'Jumped Over',
          'A Lazy',
          'White Dog'
        ];

For detailed explanation of all above QnA, please watch this video :

Courtesy : www.pngegg.com