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Re: trim() magic

by dragonchild (Archbishop)
on Mar 30, 2005 at 14:21 UTC ( #443464=note: print w/ replies, xml ) Need Help??


in reply to trim() magic

On the theory that storing the return from wantarray is always faster than computing it between 2 and 4 times, I was going to suggest the following:

sub trim { if (defined my $w = wantarray) { @_ = ( @_ ? @_ : $_ ); for (@_) { s/^\s+//, s/\s+$// if $_ } return $w ? @_ : $_[0]; } else { for (@_ ? @_ : $_) { s/^\s+//, s/\s+$// if $_ } } }
The if $_ is to protect against warnings for undefined values.

Unfortunately, it turns out that I was wrong. Your version is usually faster than mine. The only place I'm faster is my $x = trim();. I'm not sure that case is worth making the code harder to read. (Though, if this were added to something like Scalar::Util, I would code it my way.)

cmpthese( -1, { japhy => sub { $_ = ' asdf '; trim1(); }, dchild => sub { $_ = ' asdf '; trim2(); }, }); Rate dchild japhy dchild 82708/s -- -3% japhy 85163/s 3% -- cmpthese( -1, { japhy => sub { $_ = ' asdf '; my $n = trim1(); }, dchild => sub { $_ = ' asdf '; my $n = trim2(); }, }); Rate japhy dchild japhy 42766/s -- -12% dchild 48873/s 14% -- cmpthese( -1, { japhy => sub { my $x = ' asdf '; my $n = trim1( $x ); }, dchild => sub { my $x = ' asdf '; my $n = trim2( $x ); }, }); Rate dchild japhy dchild 47733/s -- -5% japhy 50243/s 5% -- cmpthese( -1, { japhy => sub { $_ = ' asdf '; my @n = trim1( ); }, dchild => sub { $_ = ' asdf '; my @n = trim2( ); }, }); Rate japhy dchild japhy 39628/s -- -8% dchild 43115/s 9% -- cmpthese( -1, { japhy => sub { my @l = (' asdf '); my @n = trim1(@l); }, dchild => sub { my @l = (' asdf '); my @n = trim2(@l); }, }); Rate dchild japhy dchild 39628/s -- -3% japhy 40959/s 3% --

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