Re: Re: Fastest (Golfish) way to strip whitspace off ends.

How should that be implemented? I think this should work just like all forms of the built-in chomp except it should remove more than trailing newlines. However, the argumentless form doesn't seem to work (doesn't propagate the lvalue context on the caller's $_) as I would expect it should. What's the right way of falling back to the caller's lvalue $_ if there's no arguments?

sub trim
{
    @_ = ($_) if not @_;  # doesn't work
    foreach (@_)
    {
        s/^\s*//;
        s/\s*$//;
        s/\n\z//s;
    }
    return wantarray? @_ : $_[0];
}
[download]

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Re: Re: Re: Fastest (Golfish) way to strip whitspace off ends. by BrowserUk (Patriarch) on Jul 02, 2003 at 17:21 UTC
Here's a couple of ways, but neither is necessarially the best way. `sub trim { @_ = ($_) if not @_; foreach my $s (@_) { $s =~ s/^\s//; $s =~ s/\s$//; $s =~ s/\n\z//s; } return wantarray? @_ : $_[0]; }` [download] Or `sub trim { @_ = ($_) if not @_; local $_; foreach (@_) { s/^\s//; s/\s$//; s/\n\z//s; } return wantarray? @_ : $_[0]; }` [download] I think that the problem with your implementation was that you were stomping on the aliasing of $_ by re-using the global $_ implicitly in your foreach loop. Using either a my'd var or localising $_ after the assignment to @_ but before the foreach loop seems to fix the problem, though I have a gut feel that there is probably a better way. Examine what is said, not who speaks. "Efficiency is intelligent laziness." -David Dunham "When I'm working on a problem, I never think about beauty. I think only how to solve the problem. But when I have finished, if the solution is not beautiful, I know it is wrong." -Richard Buckminster Fuller	[reply] [d/l] [select]
Re: Re: Re: Fastest (Golfish) way to strip whitspace off ends. by Enlil (Parson) on Jul 02, 2003 at 22:32 UTC
Halley, I am curious as to what `s/\n\z//s` would actually substitute that the previous two substitutions already had not. AFAICT, the `\n\z` would match any newlines before the end of the string, which should have been already taken care of `s/\s$//;` (as \n is matched by \s) should have captured anyway (i might be missing something here, so please correct me if i am wrong.) Also, I believe that \s+ should be faster(more efficient) in this case than \s . -enlil	[reply] [d/l] [select]