Perl | y Operator

The y operator in Perl is used to translate or substitute characters in a string. It is also known as the transliteration operator.

Syntax

$string =~ y/SEARCHLIST/REPLACEMENTLIST/;

Parameters

The y operator takes two parameters:

• SEARCHLIST: A list of characters to search for in the string.
• REPLACEMENTLIST: A list of replacement characters for the specified characters in SEARCHLIST.

The SEARCHLIST and REPLACEMENTLIST parameters must have the same number of characters. If the REPLACEMENTLIST is shorter than the SEARCHLIST, the last character in the REPLACEMENTLIST is used for all remaining characters in SEARCHLIST.

Examples

Transliteration

In the following example, the y operator is used to replace all occurrences of the character a in the string $string with the character b:

my $string = "hello world";
$string =~ y/a/b/;
print $string;  # "hello world" becomes "hello world"

Multiple replacements

The y operator can also be used to replace multiple characters in a single operation. In the following example, the y operator is used to replace all vowels in the string $string with the character *:

my $string = "hello world";
$string =~ y/aeiou/*/;
print $string;  # "hello world" becomes "h*ll* w*rld"

Case-insensitive replacements

The y operator can be used to perform case-insensitive replacements by using the i modifier:

my $string = "Hello World";
$string =~ y/a-z/A-Z/i;
print $string;  # "Hello World" becomes "HELLO WORLD"

Conclusion

The y operator is a powerful tool for performing character substitutions in Perl. It is commonly used for tasks such as converting between uppercase and lowercase characters, removing or replacing specific characters, or even removing entire blocks of text. With its simple syntax and flexible options, it is a valuable tool for any Perl programmer to have in their toolkit.