Regex to match expression followed by lower case character

Question

I want to match a closing tag followed by an 0+ spaces/newlines followed by an opening tag when followed by a lowercase letter. Examples:

text blah matches  
textand more text but not this matches 
text And more text does not match

I tried this: </.*?>\s*\n*\s*<.*>(?=[a-z]), but it doesn't work for the second example, as it will match  and more text  even though the question mark should make it "lazy".

Why not use a HTML parser instead? Regular expressions are *not* the tool to try and handle HTML; it'll lead to [pain and anguish](http://stackoverflow.com/questions/1732348/regex-match-open-tags-except-xhtml-self-contained-tags).. — Martijn Pieters, Mar 01 '14 at 18:34

score 0 · Answer 1 · answered Mar 01 '14 at 18:35

Making a quantifier lazy only makes the regex try the shortest possible match first, but if that doesn't work, it will gladly expand the match until the entire regex succeeds.

You need to be more specific in what you allow to match - for example by not allowing angle brackets inside a tag:

</[^<>]*>\s*<[^/][^<>]*>(?=[a-z])

(Also, \s already contains \n, so \s*\n*\s* can be shortened to \s*)

score 0 · Accepted Answer · answered Mar 01 '14 at 18:38

0

Try:

</[^>]+>\s*<[^/>]+>(?=[a-z])

Change the '+' to '*' if you want to be able to match empty tags

answered Mar 01 '14 at 18:38

Ron Rosenfeld

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Regex to match expression followed by lower case character

2 Answers2