Replace with regex keeping part of the pattern

Question

In the example below, how to preserve part of a pattern? The pattern search must include closing tag </h3> as spans elsewhere must not be targeted.

Example: remove only </span> from </span> some text </h3>:

regEx.Pattern = "</span>[^>]*</h3>"
hr2 = regEx.Replace(hr2,"[^>]*</h3>")  '<- does not work

Try `regEx.Pattern = "([^>]*)" // hr2 = regEx.Replace(hr2,"$1")` — Wiktor Stribiżew, Jul 22 '15 at 14:55
This did the same as what did not work above - passed it through, in this case as '$1'. — Paul, Jul 22 '15 at 15:12
Sorry, your solution correct. Did not notice the brackets in the pattern above that make $1 work. Thanks for fast help! — Paul, Jul 22 '15 at 15:17

score 3 · Accepted Answer · answered Jul 22 '15 at 15:34

3

You need to set a capturing group and use a back reference in the replacement pattern.

regEx.Pattern = "</span>([^>]*)</h3>"
hr2 = regEx.Replace(hr2,"$1</h3>")

Or

regEx.Pattern = "</span>([^>]*</h3>)"
hr2 = regEx.Replace(hr2,"$1")

answered Jul 22 '15 at 15:34

Wiktor Stribiżew

It may be worth considering using the non-greedy expression `.*?` instead of `[^>]*` in case there are other tags between `` and ``. – Ansgar Wiechers Jul 22 '15 at 15:45
Yes, but we do not know the input text. Surely `.*?` will also capture the tags before `` then. – Wiktor Stribiżew Jul 22 '15 at 15:47
`(.*?)` would capture tags between `` and ``, yes. – Ansgar Wiechers Jul 22 '15 at 15:56

1 Answers1