# in qw

Brovnik has asked for the wisdom of the Perl Monks concerning the following question:

Replies are listed 'Best First'.
Re: # in qw by blakem (Monsignor) on Sep 11, 2001 at 13:45 UTC
ObMapHack: If all your elements start with '#' you can rip it out, then put it back in using map.... `for (map {"#$_"} qw(FF0000 00FF00 0000FF))` [download] As in: `#!/usr/bin/perl -wT use strict; print "$_ " for (map {"#$_"} qw(FF0000 00FF00 0000FF)); print "\n"; =output #FF0000 #00FF00 #0000FF` [download] -Blake	[reply] [d/l] [select]
Re: # in qw by davorg (Chancellor) on Sep 11, 2001 at 13:30 UTC
Best solution is probably to not use `qw()` in that case. `for ('#FF0000', '#00FF00', '#0000FF')` [download] really isn't that much more typing :) -- <http://www.dave.org.uk> Perl Training in the UK <http://www.iterative-software.com>	[reply] [d/l]
Re: # in qw by blakem (Monsignor) on Sep 11, 2001 at 13:39 UTC
hmmm, I don't believe you can... from perlop qw/STRING/ Returns a list of the words extracted out of STRING, using embedded wh +itespace as the word delimiters. It is exactly equivalent to split(' ', q/STRING/); This equivalency means that if used in scalar context, you'll get spli +t's (unfortunate) scalar context behavior, complete with mysterious warnings. Some frequently seen examples: use POSIX qw( setlocale localeconv ) @EXPORT = qw( foo bar baz ); A common mistake is to try to separate the words with comma or to put +comments into a multi-line perlman:perlop-string. For this reason the -w switch produc +e warnings if the STRING contains the ``,'' or the ``#'' character. [download] Reading that last part, it sounds like '#' will cause a warning in qw no matter what (well as long as warnings are on) Looks like you might be stuck with something like: `split(' ',q/#FF0000 #00FF00 #0000FF/)` [download] As in: `#!/usr/bin/perl -wT use strict; print "$_ " for (qw ( #FF0000 #00FF00 #0000FF )); print "\n"; print "$_ " for (split(' ',q/#FF0000 #00FF00 #0000FF/)); print "\n"; =output Possible attempt to put comments in qw() list at ./qw.pl line 4. #FF0000 #00FF00 #0000FF #FF0000 #00FF00 #0000FF` [download] note, the warning is from the original style qw quoting... comment that out, and the warning will be gone. </code> -Blake	[reply] [d/l] [select]
Re: # in qw by virtualsue (Vicar) on Sep 11, 2001 at 13:19 UTC
Use single quotes or q// to avoid interpolation of the list elements and the warning will go away. `for (q/#FF0000 #00FF00 #0000FF/)` Update: D'oh!! See replies below. `for (q/#FF0000/, q/#00FF00/, q/#0000FF/)` would also work, but it's more typing.	[reply] [d/l] [select]
Re: Re: # in qw by busunsl (Vicar) on Sep 11, 2001 at 13:28 UTC
But `q//` will not return a list! `qw//` does.	[reply] [d/l] [select]
Re: Re: Re: # in qw by virtualsue (Vicar) on Sep 11, 2001 at 13:39 UTC
That's true, I just realized it. `for (split /\s+/, q/#FF000 #00FF00 #0000FF/) or for ('#FF000', '#00FF00', '#0000FF')` [download]	[reply] [d/l]
Re: # in qw by busunsl (Vicar) on Sep 11, 2001 at 13:23 UTC
I assume thie script runs with `-w` or `use warnings`. So all I can come up with is drop warnings for the block in question: `no warnings 'syntax'; for (qw ( #FF0000 #00FF00 #0000FF )) ... use warnings 'syntax';` [download]	[reply] [d/l] [select]
(tye)Re: # in qw by tye (Sage) on Sep 11, 2001 at 20:19 UTC
That is an excellent idea. qw() already supports \ for escaping the closing delimiter (or repeats of the opening delimiter when using "paired" delimiters). So it makes sense to support "\," and "\#" to avoid the warnings and to support "\ " for including whitespace inside "words". Unfortunately, that isn't currently the case (and there would be a very minor backward compatability issue). - tye (but my friends call me "Tye")	[reply]


XP is just a number
	PerlMonks