in reply to Re: Re: Help with null string behavior in regex?
in thread Help with null string behavior in regex?

I hoped that what I was doing was clear enough. The real improvements were doing a chomp() on the whole list at once, only once, removing any empty elements, then pre-compiling all the patterns.

I also changed your for ( ... ) { unless ( ... ) { ...; last } } because it read strangely for me. unless() is like that, sometimes it just reads strangely. Since the intent of that code was to be an "everything matches or I print the file name" I just skipped right to the next pattern if there was a match and made the exception stand out.

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Re: Re: Re: Re: Help with null string behavior in regex?
by McMahon (Chaplain) on May 03, 2004 at 23:53 UTC
    It's definitely clear! But "grep length" and "map qr" haven't made it into my syntactical bag yet.

    I get new stuff to read about every time I post code here.

    BTW, I didn't know "chomp @array" was possible. I posted a question recently trying to "lc @array", which *isn't* possible, so I just figured the same rule applied.
[reply]

      Oh ok. This is easy enough.

      @foo = grep length(), @foo;

# is equivalent to but faster and clearer than

my @tmp;
for my $element_of_foo ( @foo )
{
    if ( length( $element_of_foo ) > 0 )
    {
        push @tmp, $element_of_foo;
    }
}
@foo = @tmp;

      [download]

      The line @foo = map qr/$_/, @foo; could be omitted from your program with no effect except of being slower. You'll see notes on qr// in perlop. The entire point is to pre-compile each regular expression so that when you do tests against it later perl won't have to do everything on the fly (and everytime you test a new file).

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