How can is select XML tag that contains specific XML tag with specific text inside using regual expressions?

Question

I have XML text. In that XML text I have tags named <pskc:KeyPackage> this tag may or may not contain different tags and one of that tag may be <pskc:IssueNo>1</pskc:IssueNo>. With regular expressions i want to select all <pskc:KeyPackage> tags, which contain <pskc:IssueNo>1</pskc:IssueNo> tag. How can i accomplish this?

please see regex on flowing link: https://regex101.com/r/7HICeu/2

This is my sample input:

<pskc:KeyPackage>  

 <testTag>val1</testTag>

  <pskc:IssueNo>1</pskc:IssueNo>

  <testTag2>val2</testTag2>

</pskc:KeyPackage>
  <pskc:KeyPackage>

      <pskc:IssueNo>2</pskc:IssueNo>

  </pskc:KeyPackage>
  <pskc:KeyPackage>

      <pskc:IssueNo>3</pskc:IssueNo>

  </pskc:KeyPackage>
  <pskc:KeyPackage>

      <pskc:IssueNo>1</pskc:IssueNo>

  </pskc:KeyPackage>
  <pskc:KeyPackage>

      <pskc:IssueNo>2</pskc:IssueNo>

  </pskc:KeyPackage>
  <pskc:KeyPackage>

      <pskc:IssueNo>3</pskc:IssueNo>

  </pskc:KeyPackage>
  <pskc:KeyPackage>

      <pskc:IssueNo>1</pskc:IssueNo>

  </pskc:KeyPackage>
  <pskc:KeyPackage>

      <pskc:IssueNo>2</pskc:IssueNo>

  </pskc:KeyPackage>
  <pskc:KeyPackage>

      <pskc:IssueNo>3</pskc:IssueNo>

  </pskc:KeyPackage>
  <pskc:KeyPackage>

      <pskc:IssueNo>1</pskc:IssueNo>

  </pskc:KeyPackage>
  <pskc:KeyPackage>

      <pskc:IssueNo>2</pskc:IssueNo>

  </pskc:KeyPackage>
  <pskc:KeyPackage>

      <pskc:IssueNo>3</pskc:IssueNo>

  </pskc:KeyPackage>
  <pskc:KeyPackage>

      <pskc:IssueNo>1</pskc:IssueNo>

  </pskc:KeyPackage>
  <pskc:KeyPackage>

      <pskc:IssueNo>2</pskc:IssueNo>

  </pskc:KeyPackage>
  <pskc:KeyPackage>

      <pskc:IssueNo>3</pskc:IssueNo>

  </pskc:KeyPackage>

i want to mach following tags:

<pskc:KeyPackage>  

 <testTag>val1</testTag>

  <pskc:IssueNo>1</pskc:IssueNo>

  <testTag2>val2</testTag2>

</pskc:KeyPackage>

and i also want to match each tag that look like this:

  <pskc:KeyPackage>

      <pskc:IssueNo>1</pskc:IssueNo>

  </pskc:KeyPackage>

I want to say again that <pskc:KeyPackage> tag will contain many different tags, like it does in following example:

<pskc:KeyPackage>  

 <testTag>val1</testTag>

  <pskc:IssueNo>1</pskc:IssueNo>

  <testTag2>val2</testTag2>

</pskc:KeyPackage>

I want to mach the whole <pskc:KeyPackage> tag only if it contains <pskc:IssueNo>1</pskc:IssueNo>. How can i accomplish this?

P.S. I have also tried many different regex-es, on of them is following regex: <pskc:KeyPackage>[\s\S]*<pskc:IssueNo>1<\/pskc:IssueNo>[\s\S]*<pskc:KeyPackage> but it maches whole xml string.

Thank you

Can you copy the example input in the question e write what you want to match? — Enlico, Feb 14 '20 at 06:55
Why would you want to do this with regex? (https://stackoverflow.com/a/1732454/317052) A simple xpath could be used: `//pskc:KeyPackage[pskc:IssueNo='1']` — Daniel Haley, Feb 14 '20 at 17:13
@TornikeShavishvili, I think I have the regex you are looking for in [my answer](https://stackoverflow.com/a/60231964/5825294). — Enlico, Feb 14 '20 at 19:03

Enlico · Accepted Answer · 2020-02-14T19:24:21.760

This works:

/<pskc:KeyPackage>((?!<\/pskc:KeyPackage>).)*<pskc:IssueNo>1<\/pskc:IssueNo>.*?<\/pskc:KeyPackage>/gs

(I don't know all regex flavors, but it looks like this works for Perl, JS, and Python.)

How it works:

it matches <pskc:KeyPackage>,
followed by any amount (the first *) of any characters (the first .) including newlines (the s flag), each of which matches where </pskc:KeyPackage> does not match ((?!…)),
followed by <pskc:IssueNo>1</pskc:IssueNo>.
Then it also matches up the the closest (.*?) closing </pskc:KeyPackage>.

Other two details:

/s need to be escaped, \/,
depending on your application, you might want to use non-capturing parentheses for the first group (change the first ( to (?:), whose sole purpose is to let you apply the first * to it.

I have learned new things about regular expressions and better understand them now thanks to this answer — Tornike Shavishvili, Feb 14 '20 at 23:03

How can is select XML tag that contains specific XML tag with specific text inside using regual expressions?

1 Answers1