Uri Guttman wrote:
"JWK" == John W Krahn<jwkr...@shaw.ca> writes:
JWK> Or as:
JWK> $_ = "$directory/$_" for @dirfiles[ 1 .. $#dirfiles ];
just to show another way that is usually faster for prepending a string:
substr( $_, 0, 0, "$directory/" ) for @dirfiles[ 1 .. $#dirfiles ];
that is called 4 arg substr and it is way underused in perl. this
benchmark shows the significant speedup of about 2x:
use Benchmark qw( cmpthese ) ;
cmpthese ( shift || -2, {
assign => sub { my $x = 'abc' ; $x = "qwerty/$x" },
substr => sub { my $x = 'abc' ; substr( $x, 0, 0, 'qwerty/') },
}
) ;
Rate assign substr
assign 2356409/s -- -47%
substr 4428292/s 88% --
I'm not seeing it:
$ perl -le'
use Benchmark qw( cmpthese );
cmpthese ( shift || -2, {
assign => sub { my $x = "abc"; my $dir = "qwerty"; $x = "$dir/$x" },
substr => sub { my $x = "abc"; my $dir = "qwerty"; substr $x, 0, 0,
"$dir/" },
} );
'
Rate substr assign
substr 997968/s -- -2%
assign 1018371/s 2% --
John
--
Any intelligent fool can make things bigger and
more complex... It takes a touch of genius -
and a lot of courage to move in the opposite
direction. -- Albert Einstein
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
