regex search and replace issue

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


if (lc($Message) =~ /^db /) {
print "Content-type:text/html\n\n";
print "c=$Message<br>\n";
  $Message = s/^db //;
  $Message = s/^Db //;
  $Message = s/^dB //;
  $Message = s/^DB //;
print "m=$Message";
exit;
}
[download]

gives result:

c=Db test4<br>
m=
[download]

I'm expecting the Db(space) to be removed but the whole expression is being taken out!

Comment on regex search and replace issue Select or Download Code

Replies are listed 'Best First'.
Re: regex search and replace issue by Anonymous Monk on Nov 11, 2011 at 08:21 UTC
Assignment operator `=` is not the same as binding operator `=~` If you want to make matches, or substitutions, on $variable, you need to use binding operator	[reply]
Re^2: regex search and replace issue by jonnyfolk (Vicar) on Nov 11, 2011 at 11:40 UTC
oh, I'm as careless as careless can be. Thanks to all for pointing it out and helpful suggestions	[reply]
Re^3: regex search and replace issue (strictures) by toolic (Bishop) on Nov 11, 2011 at 13:49 UTC
Perl can help prevent you from being careless... if you use strict and warnings. You would have gotten a warning message which would have pointed you to the offending lines.	[reply]
Re: regex search and replace issue by MVS (Monk) on Nov 11, 2011 at 08:26 UTC
Anonymous Monk has the right solution, but just wanted to add that you can simplify your regexes using character classes. You can replace all four with: `$Message =~ s/^[Dd][Bb] //;`	[reply] [d/l]
Re^2: regex search and replace issue by Utilitarian (Vicar) on Nov 11, 2011 at 08:57 UTC
Or by using the case insensitivity modifier to the regex. `$Message =~ s/^db //i;` [download] `print "Good ",qw(night morning afternoon evening)[(localtime)[2]/6]," fellow monks."`	[reply] [d/l] [select]
Re: regex search and replace issue by mrstlee (Beadle) on Nov 11, 2011 at 10:05 UTC
Just to flesh out Utilitarian's answer: `if ($Message =~ /^db /i) { print "Content-type:text/html\n\n"; print "c=$Message<br>\n"; $Message =~ s/^db //i; print "[m=$Message]\n"; exit; }` [download]	[reply] [d/l]
Re^2: regex search and replace issue by hbm (Hermit) on Nov 11, 2011 at 14:29 UTC
Or, since you're exiting and therefore don't need the modified $Message further down, just capture any trailing stuff and print once: `if ($Message =~ /db (.*)/i){ print "Content-type:text/html\n\n", "c=$Message<br>\n", "[m=$1]\n"; exit; }` [download]	[reply] [d/l]