>>>>> "David" == David Gray <[EMAIL PROTECTED]> writes:
David> When you have
David> LIST2 = map { m!^(.*)/\*$! } LIST1
David> It's shorthand for a loop like:
David> foreach my $el (@LIST1) {
David> if($el =~ m!^(.*?)/\*$!) {
David> push @LIST2,$1
David> } else {
David> push @LIST2,()
David> }
David> }
Not really. Don't muddle that up with an extra 'if', or you'll be implying
some Extra Magick in the map operator. The map operator is dumb as rocks.
It just takes the last expr evaluated *in a list context* and appends
it to the end of the result list. If anything, the "smooth operator" here
is the regex match in a list context!
So it's closer to this:
@LIST2 = ();
foreach (@LIST1) {
my @result = m!^(.*?)/\*$!;
## at this point, @result is either $1 for a match, or () for a non match
push @LIST2, @result;
## and thus we've either pushed $1 (single element) or empty list (nothing)
}
David> So when the regular expression doesn't match, it pushes an empty list,
David> which adds nothing to the array.
Yes, but not by the mechanism you're illustrating.
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