Perl: function to trim string leading and trailing whitespace

Question

Is there a built-in function to trim leading and trailing whitespace such that trim(\" hello world \") eq \"hello world\"?

Answer 1

For those that are using Text::CSV I found this thread and then noticed within the CSV module that you could strip it out via switch:

$csv = Text::CSV->new({allow_whitespace => 1});

The logic is backwards in that if you want to strip then you set to 1. Go figure. Hope this helps anyone.

Answer 2

There's no built-in trim function, but you can easily implement your own using a simple substitution:

sub trim {
    (my $s = $_[0]) =~ s/^\s+|\s+$//g;
    return $s;
}

or using non-destructive substitution in Perl 5.14 and later:

sub trim {
   return $_[0] =~ s/^\s+|\s+$//rg;
}

Answer 3

Complete howto in the perfaq here: http://learn.perl.org/faq/perlfaq4.html#How-do-I-strip-blank-space-from-the-beginning-end-of-a-string-

Answer 4

One option is Text::Trim:

use Text::Trim;
print trim("  example  ");

Answer 5

Apply: s/^\s*//; s/\s+$//; to it. Or use s/^\s+|\s+$//g if you want to be fancy.

Answer 6

Here's one approach using a regular expression:

$string =~ s/^\s+|\s+$//g ;     # remove both leading and trailing whitespace

Perl 6 will include a trim function:

$string .= trim;

Source: Wikipedia