RE: My favorite looping mechanism in Perl is:

Replies are listed 'Best First'.
RE: RE: My favorite looping mechanism in Perl is: by merlyn (Sage) on May 13, 2000 at 04:30 UTC
Don't use `map` in a void context. Now that the backwards foreach is in there, it's never necessary. And it's also wasteful.	[reply]
RE: RE: RE: My favorite looping mechanism in Perl is: by marcos (Scribe) on May 15, 2000 at 12:35 UTC
Thank you for your note, but could you please explain why using map in void context is "a wasteful"? Is it a problem of code performance and/or optimization? TIA, marcos	[reply]
RE: RE: RE: RE: My favorite looping mechanism in Perl is: by btrott (Parson) on May 15, 2000 at 20:56 UTC
I believe it is/was wasteful because of the list that map builds to return to you. The normal use of map is like this: `my @returned = map BLOCK LIST;` [download] In order to fill up @returned, map has to build a list. If you're not going to be using that list (if you're using map in void context), you've wasted that storage and the processing time needed to allocate that memory. However, I've read bits and pieces of this discussion in the past, and I had thought that this list-building was optimized away when map is used in a void context. Is this the case, or was that merely a suggestion? :)	[reply] [d/l]
RE: RE: My favorite looping mechanism in Perl is: by ChuckularOne (Prior) on May 10, 2000 at 15:43 UTC
map! Map! MAP! I love it. I have never used it, and now I'm thinking of all of the extra lines of code I've written over time to do what a simple map does!!! Thank you! I think I have a new favorite widget for the week! Your humble servant, -Chuck	[reply]
RE: RE: RE: My favorite looping mechanism in Perl is: by marcos (Scribe) on May 10, 2000 at 20:40 UTC
This is the same reaction I had when I discovered map :-) I'm not sure if it is a real looping mechanism (technically speaking): if you check the manpage it says "map - apply a change to a list to get back a new list with the changes". Anyway I think it is very powerful, and very beautiful, and I use whenever I can! marcos	[reply]


laziness, impatience, and hubris
	PerlMonks