Regex capture only numbers inside specific tag

Question

I have the following text

<msgText>H3ll0World</msgText><msgText>HelloWorld</msgText><otherTagWithNumbers>456</otherTagWithNumbers>

I need to retrive only the numbers ( [\d] ) inside the tag <msgText> in order to replace them. In this case the regex would return 3 and 0.

What I have so far:

(<msgText>)([\s\S]*?)(<\/msgText>)

Here I have an example of this situation.

Try this [`\d+(?=(?:(?!<\/?\w+>).)*<\/msgText>)`](https://regex101.com/r/0zGJMj/4) — revo, Mar 09 '18 at 20:58
you should consult [how to ask a question](https://stackoverflow.com/help/how-to-ask). where's the code where you tried something? — , Mar 09 '18 at 20:59

score 1 · Answer 1 · answered Mar 09 '18 at 21:11

1

You are trying to parse XML with regex, again...

But maybe this works on some extremely restricted subset of XML that you are dealing with:

(\d+)(?=\w*<\/msgText>)

answered Mar 09 '18 at 21:11

Andrey Tyukin

Thanks bro. I'm not trying to parse a XML, I just want to replace numbers inside a specific tag. Thanks again! – Joabe Lucena Mar 09 '18 at 21:17
@JoabeLucena Yeah, I understand that, it was just the obligatory disclaimer that XML is not regular, like for any other "regex + (X/HT)ML" question ;) Glad that you could solve your problem despite all the theoretical obstacles xD – Andrey Tyukin Mar 10 '18 at 02:01

score 1 · Accepted Answer · answered Mar 09 '18 at 21:14

You'd like to use a positive lookahead to look but not consume:

\d+(?=(?:(?!<\/?\w+>).)*<\/msgText>)

Breakdown:

\d+ Match any number
(?= That is followed by
- (?:(?!<\/?\w+>).)* A tempered greedy token to match anything but not pass over tags
- <\/msgText> Up to a closing tag
) End of positive lookahead

Above is a strict match but there is a short way to achieve the same under some circumstances:

\d+(?=[^<]*<\/msgText>)

2 Answers2