Re: regexp need a match characters and spaces

Replies are listed 'Best First'.
Re^2: regexp need a match characters and spaces by johngg (Canon) on Mar 23, 2006 at 14:48 UTC
You could try the following as it seems to cope with spaces between the b and it's newline and with b with an immediate newline by making the spaces optional and also making a character class that excludes newline, unlike `\s`. Set up some text to try and set up the regular expression. `#!/usr/local/bin/perl # use strict; use warnings; our @tryThese = ( "a 10\nb a2 s2\nc 30", "a 10\nb\nc 30", "a 10\nb \nc 30", "a 10\nb a2 s2 \nc 30"); our $c; our $rxAfterB = qr{(?m)^b[\x20\x09]([^\n])};` [download] Loop over `@tryThese` printing out what we are testing, doing the match then showing the result. `foreach my $a (@tryThese) { print "\n\$a contains ...\n"; { local $" = "<--\n"; print "@{[split /\n/, $a]}\n"; } ($c) = $a =~ /$rxAfterB/; print "c is -->$c<--\n\n"; }` [download] When run this produces `$a contains ... a 10<-- b a2 s2<-- c 30 c is -->a2 s2<-- $a contains ... a 10<-- b<-- c 30 c is --><-- $a contains ... a 10<-- b <-- c 30 c is --><-- $a contains ... a 10<-- b a2 s2 <-- c 30 c is -->a2 s2 <--` [download] I hope this is of use. Cheers, JohnGG Update: The slashes around the compiled regular expression in the line `($c) = $a =~ /$rxAfterB/;` are superfluous. The line should read `($c) = $a =~ $rxAfterB;` [download] JohnGG	[reply] [d/l] [select]
Re^2: regexp need a match characters and spaces by graff (Chancellor) on Mar 23, 2006 at 23:27 UTC
I think the solution given by codeacrobat is the best one, but if you wanted to insist on working with the one scalar value containing multiple lines, maybe something like this: `$a = " a 10 b a2 s2 c 30"; ( $c ) = $a =~ /^b[ \t]+(.)/m; print "$c\n";` [download] That is, simply make sure you don't include "\n" among the kinds of white-space that can follow "b" in order to yield a match. (BTW, you want everything on the line that starts with "b", and the "m" modifier on the regex does not affect the behavior of "." -- it still will not match "\n", so the question mark and dollar sign in the OP version -- (.?)$ -- are redundant here.)	[reply] [d/l]