How to trim whitespace with a custom subroutine in Perl

mariusvw — Tue, 14 Jun 2011 18:00:50 +0000

Since perl does not have a built-in trim function (yet). Use the subroutine below to trim whitespace (spaces and tabs) from the beginning and end of a string in Perl. This function is directly based on the Perl FAQ entry, How do I strip blank space from the beginning/end of a string?. The ltrim and rtrim functions can trim leading or trailing whitespace.

#!/usr/bin/perl
 
# Declare the subroutines
sub trim($);
sub ltrim($);
sub rtrim($);
 
# Create a test string
my $string = "  \t  Hello world!   ";
 
# Here is how to output the trimmed text "Hello world!"
print trim($string)."\n";
print ltrim($string)."\n";
print rtrim($string)."\n";
 
# Perl trim function to remove whitespace from the start and end of the string
sub trim($) {
	my $string = shift;
	$string =~ s/^\s+//;
	$string =~ s/\s+$//;
	return $string;
}
# Left trim function to remove leading whitespace
sub ltrim($) {
	my $string = shift;
	$string =~ s/^\s+//;
	return $string;
}
# Right trim function to remove trailing whitespace
sub rtrim($) {
	my $string = shift;
	$string =~ s/\s+$//;
	return $string;
}

Marius van Witzenburg » Trim

How to trim whitespace with a custom subroutine in Perl