Regexp, how to limit a match

Question

I have a string:

string = %q{<span class="no">2503</span>read_attribute_before_type_cast(<span class="pc">self</span>.class.primary_key)}

In this example I want to match the words 'class' which are not in the tag. Regexp for this:

/\bclass[^=]/

But the problem is that it matches the last letter

/\bclass[^=]/.match(string) => 'class.'

I don't want have a last dot in a result. I've tried this regexp:

/\bclass(?:[^=])/

but still got the same result. How to limit the result to 'class'? Thanks

Possibly related question: http://stackoverflow.com/q/1732348/38765 — Andrew Grimm, Jun 08 '11 at 23:36

score 2 · Accepted Answer · answered Jun 08 '11 at 03:28

2

You are almost correct, but you have an error in your look ahead. Try this:

/\bclass(?!=)/

The regex term (?!=) means the input to the right must not match the character '='

answered Jun 08 '11 at 03:28

Bohemian

score 0 · Answer 2 · answered Jun 08 '11 at 03:20

0

You can take your variable string and extract a subsection using groups:

substring = string[/\b(class)[^=]/, 1]

The brackets around class will set that as the first "group", which is referred to by the 1 as the second parameter in the square brackets.

answered Jun 08 '11 at 03:20

robbrit

Clumsy. Use a (non-consuming) regex look ahead - see my answer – Bohemian Jun 08 '11 at 03:29

score 0 · Answer 3 · answered Jun 08 '11 at 03:21

0

Assuming your only issue is keeping it from matching span.class.blah, just ignore . as well, so [^=.].

answered Jun 08 '11 at 03:21

Sysyphus

3 Answers3