in reply to Replace consecutive whitespaces with single whitespace

Your replacement needs to be a space. \s is not a way to write that. 
$str ="Any    help would   be    greatly      appreciated";
$str =~ s/\s+/ /g;
print $str;

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Re^2: Replace consecutive whitespaces with single whitespace
by JavaFan (Canon) on Mar 26, 2009 at 12:47 UTC
    To avoid Perl doing work when it doesn't have to, I prefer to write that as: 
    $str =~ s/\s{2,}/ /g;

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    Note also that using \s matches more than the space the OP mentioned. In particular, s/\s+/ /g or s/\s{2,}/ /g will replace one (two) or more newlines with a space.
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      As for the newline issue, I thought of that, and then I thought that the OP quite possibly had data with tabs in it rather than multiple spaces. In that case you would want to match more than just spaces. You would also want to replace a single tab with a single space.

      Besides which, the extra work is negligible - if you care about that small of an efficiency then Perl is probably the wrong language to use in the first place.

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        Besides which, the extra work is negligible
        Maybe, maybe not. Whether it's negligible or not depends on the data at hand. If you have a long string with many single spaces it does matter as you avoid copying the string. 
        our $str = "x " x 1000;

cmpthese -1, {
    single => sub {local $_ = $::str; s/\s+/ /g},
    multiple => sub {local $_ = $::str; s/\s{2,}/ /g;}
};
__END__
           Rate   single multiple
single   1969/s       --     -40%
multiple 3287/s      67%       --

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        Copying the string on each single space is an inefficient algorithm.
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