Re^4: Two hash keys created when '.' is in the string

"And finally, running any regexp match overwrites the values of all the number variables (for instance, $2), so after checking $2 =~ /css/i, $2 will be undef."

Not true. Perl doesn't garuntee that it will overright those unless they actualy match. Since that regex isn't doing any captures he should be safe, not that I think its the best way to do it, but its safe.

___________
Eric Hodges

Comment on Re^4: Two hash keys created when '.' is in the string

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Re^5: Two hash keys created when '.' is in the string by ikegami (Patriarch) on Nov 24, 2004 at 19:04 UTC
"Since that regex isn't doing any captures he should be safe" is wrong. Captures or not, $2 is cleared on a successful match. `$cfm = 'moo'; 'moo' =~ /()(.)/; if (($2 =~ /css/i) \|\| ($2 eq $cfm)) { print(defined($2)?1:0, $/); # 1, cause match failed $uniques{$2}++; } 'css' =~ /()(.)/; if (($2 =~ /css/i) \|\| ($2 eq $cfm)) { print(defined($2)?1:0, $/); # 0, cause match succeeded $uniques{$2}++; # $uniques{undef} ??? }` [download]	[reply] [d/l]
Re^5: Two hash keys created when '.' is in the string by Eimi Metamorphoumai (Deacon) on Nov 24, 2004 at 18:55 UTC
You're right, it only resets them on a successful match, not on an attempted match. But it will overwrite all of them if there's a successful match, even if the match doesn't include any parens. So if the string `/css/` matches, `$2` will be undef, and in that case the code won't work right.	[reply] [d/l] [select]
Re^6: Two hash keys created when '.' is in the string by eric256 (Parson) on Nov 24, 2004 at 19:07 UTC
/me eats his words. You are 100% correct. Here is an example (that I had to run to beleive it). `my $test = "Hello world!"; print "Matched\n" if $test =~ /(Hello)/; print "\$1 = $1\n"; print "Matched\n" if $test =~ /world/; print "\$1 = $1\n"; __DATA__ Matched $1 = Hello Matched $1 =` [download] ___________ Eric Hodges	[reply] [d/l]