Text::Trim(3) remove leading and/or trailing whitespace from strings


version 1.02


use Text::Trim;
$text = "\timportant data\n";
$data = trim $text;
# now $data contains "important data" and $text is unchanged

# or:
trim $text; # work in-place, $text now contains "important data"
@lines = <STDIN>;
rtrim @lines; # remove trailing whitespace from all lines
# Alternatively:
@lines = rtrim <STDIN>;
# Or even:
while (<STDIN>) {
trim; # Change $_ in place
# ...


This module provides functions for removing leading and/or trailing whitespace from strings. It is basically a wrapper around some simple regexes with a flexible context-based interface.


All functions are exported by default.


void context

Functions called in void context change their arguments in-place

    trim(@strings); # All strings in @strings are trimmed in-place
    ltrim($text); # remove leading whitespace on $text
    rtrim; # remove trailing whitespace on $_

No changes are made to arguments in non-void contexts.

list context

Values passed in are changed and returned without affecting the originals.

    @result = trim(@strings); # @strings is unchanged
    @result = rtrim; # @result contains rtrimmed $_
    ($result) = ltrim(@strings); # like $result = ltrim($strings[0]);

scalar context

As list context but multiple arguments are stringified before being returned. Single arguments are unaffected. This means that under these circumstances, the value of $" ($LIST_SEPARATOR) is used to join the values. If you don't want this, make sure you only use single arguments when calling in scalar context.

    @strings = ("\thello\n", "\tthere\n");
    $trimmed = trim(@strings);
    # $trimmed = "hello there"
    local $" = ', ';
    $trimmed = trim(@strings);
    # Now $trimmed = "hello, there"
    $trimmed = rtrim;
    # $trimmed = $_ minus trailing whitespace

Undefined values

If any of the functions are called with undefined values, the behaviour is in general to pass them through unchanged. When stringifying a list (calling in scalar context with multiple arguments) undefined elements are excluded, but if all elements are undefined then the return value is also undefined.

    $foo = trim(undef);        # $foo is undefined
    $foo = trim(undef, undef); # $foo is undefined
    @foo = trim(undef, undef); # @foo contains 2 undefined values
    trim(@foo)                 # @foo still contains 2 undefined values
    $foo = trim('', undef);    # $foo is ''



Removes leading and trailing whitespace from all arguments, or $_ if none are provided.


Like trim() but removes only trailing (right) whitespace.


Like trim() but removes only leading (left) whitespace.


Because this module is implemented using perl regular expressions, it is capable of recognising and removing unicode whitespace characters (such as non-breaking spaces) from scalars with the utf8 flag on. See Encode for details about the utf8 flag.

Note that this only applies in the case of perl versions after 5.8.0 or so.


Matt Lawrence <[email protected]>


Terrence Brannon <[email protected]> for bringing my attention to String::Strip and suggesting documentation changes.