How do I use substring in Perl?

How do I use substring in Perl?

substr() in Perl returns a substring out of the string passed to the function starting from a given index up to the length specified. This function by default returns the remaining part of the string starting from the given index if the length is not specified.

Does Perl use Pcre?

Perl Compatible Regular Expressions (PCRE) is a library written in C, which implements a regular expression engine, inspired by the capabilities of the Perl programming language. Philip Hazel started writing PCRE in summer 1997. x and Perl 5.9. …

How do I run a Perl file?

1. Write and Run Your First Script. All you need to write Perl programs is a text editor.
2. Write Your Script. Create a new text file and type the following exactly as shown: #!usr/bin/perl.
3. Run Your Script. Back at the command prompt, change to the directory where you saved the Perl script.

How to get the value of a hash element in Perl?

The keys () function returns a list of hash’s keys. The for loop visits each key and assigns it to a special variable $_. Inside the loop, we access the value of a hash element via its key as $langs {$_}. In this tutorial, you’ve learned about Perl hash and some techniques to manipulate hash’s elements.

What is a regular expression in Perl?

A regular expression or a regex is a string of characters that define the pattern that we are viewing. It is a special string describing a search pattern present inside a given text. Perl allows us to group portions of these patterns together into a subpattern and also remembers the string matched by those subpatterns.

What is %+ in Perl?

When there’s a success of matches against the enclosing pattern, Perl updates the magical variable ‘ %+ ‘. This hash contains the name of the capture as the key and the portion of the string that matched the capture as the value of hash. Named captures often improve regex maintainability.

How to rewrite $countries hash in Perl?

The $countries hash can be rewritten using => operator as follows: Perl requires the keys of a hash to be strings, meanwhile, the values can be any scalars. If you use non-string values as the keys, you may get an unexpected result.