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How do I strip blank space from the beginning/end

Jasmine
Administrator

Jan 19, 2001, 2:56 PM

Post #1 of 1 (1939 views)

How do I strip blank space from the beginning/end	Can't Post

(From the Perl FAQ)

How do I strip blank space from the beginning/end of a string?

Although the simplest approach would seem to be:

Code

    $string =~ s/^\s*(.*?)\s*$/$1/;

This is unneccesarily slow, destructive, and fails with embedded newlines. It is much better faster to do this in two steps:

Code

    $string =~ s/^\s+//; 
    $string =~ s/\s+$//;

Or more nicely written as:

Code

    for ($string) { 
        s/^\s+//; 
        s/\s+$//; 
    }

This idiom takes advantage of the foreach loop's aliasing behavior to factor out common code. You can do this on several strings at once, or arrays, or even the values of a hash if you use a slide:

Code

    # trim whitespace in the scalar, the array,  
    # and all the values in the hash 
    foreach ($scalar, @array, @hash{keys %hash}) { 
        s/^\s+//; 
        s/\s+$//; 
    }

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