Regex in Perl

Regular expressions (regex) in Perl are used to search for and manipulate patterns in text. They are powerful tools that allow you to match and replace text based on a set of rules.

Here are some examples of how to use regex in Perl:

1. Matching a string

To match a string in Perl using regex, you can use the =~ operator:

my $string = "hello world";
if ($string =~ /world/) {
  print "Match found!\n";
}

In this example, the regex /world/ is used to match the string "world" in the variable $string.

2. Matching a specific character

You can use the square bracket notation to match a specific character:

my $string = "hello world";
if ($string =~ /[aeiou]/) {
  print "Match found!\n";
}

In this example, the regex [aeiou] is used to match any vowel character in $string.

3. Matching a range of characters

You can use the hyphen notation to match a range of characters:

my $string = "I like apples and oranges";
if ($string =~ /[a-m]/) {
  print "Match found!\n";
}

In this example, the regex [a-m] is used to match any lowercase letter from "a" to "m".

4. Matching any character

To match any character, you can use the period notation:

my $string = "hello world";
if ($string =~ /w.rld/) {
  print "Match found!\n";
}

In this example, the regex w.rld is used to match any character between "w" and "r" in $string.

5. Grouping and capturing

You can use parentheses to group and capture parts of a match:

my $string = "The quick brown fox";
if ($string =~ /The (quick \w+) fox/) {
  print "Match found: $1\n";
}

In this example, the regex The (quick \w+) fox is used to match the entire string "The quick brown fox" and capture the word "quick" as a group. $1 is used to reference the captured group.