I'll give that a try, thanks. Just cannot see why is it that .{1,3} doesn't have the same effect given the only difference is the exclusion of a 'b'. Thanks, Derrick 2007/2/15, Darren Garvey :

Hi Derrick,

On 15/02/07, Derrick Schommer wrote:

...

Hi,

I'm trying to understand if a regular expression I've designed is working correctly. It seems that I can make the regular expression match work "off by one" character in certain circumstances. For instance:

The pattern: ".{1,3}" finds 1 to 3 characters, however

The pattern: ".[^b]{1,3}" finds 1 to 4 characters...? <dice>

The reason the second patter finds 1-4 chars is because you've asked for '.' (any character) followed by [^b]{1,3} (1-3 of any character except b). If you want 1-3 of anything except b, then just "[^b]{1,3}" is all you need.

hth, Darren

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Okay, thanks, that makes a bit more sense! Derrick 2007/2/15, Chris Uzdavinis :

On 2/15/07, Derrick Schommer wrote:

...

I'll give that a try, thanks. Just cannot see why is it that .{1,3} doesn't have the same effect given the only difference is the exclusion of a 'b'.

I'm getting the impression that you have a wrong impression of regular expressions. When you say .[^b] the [^b] is not modifying the . expression. What you have are two regular expressions next to each other, first the dot (for one character), then [^b], which matches anything except b. So .[^b] matches 2 characters, "any-character followed by any-character-except-b". Now when you put the repeatitions on it, ".[^b]{1,3}" you have "any-character followed by one-to -three-characters-that-aren't-b"

Hope that helps. Chris _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users