# Named capture groups in change node's regex

**URL:** https://discourse.nodered.org/t/named-capture-groups-in-change-nodes-regex/28014
**Category:** General
**Created:** [8 June 2020 23:07 UTC](https://discourse.nodered.org/t/named-capture-groups-in-change-nodes-regex/28014 "2020-06-08T23:07:30Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![JSONata](https://avatars.discourse-cdn.com/v4/letter/j/85e7bf/32.png) [@JSONata](https://discourse.nodered.org/u/JSONata)
#### Post date: [8 June 2020 23:07 UTC](https://discourse.nodered.org/t/named-capture-groups-in-change-nodes-regex/28014/1 "2020-06-08T23:07:30Z")

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Please have a look at this flow

> [{"id":"1702a6eb.de8499","type":"inject","z":"ddd38a48.2e949","name":"","topic":"","payload":"abc1234abc","payloadType":"str","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":230,"y":1100,"wires":[["d59e679b.d56998"]]},{"id":"d59e679b.d56998","type":"change","z":"ddd38a48.2e949","name":"","rules":[{"t":"change","p":"payload","pt":"msg","from":"(?[0-9]+)","fromt":"re","to":"XX${number}XX","tot":"str"}],"action":"","property":"","from":"","to":"","reg":false,"x":570,"y":1100,"wires":[["c77e8493.720b68"]]},{"id":"c77e8493.720b68","type":"debug","z":"ddd38a48.2e949","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","x":800,"y":1100,"wires":}]

We insert string "abc1234abc"  
in Regex wie search vor the number via "(?[0-9]+)"  
Now I want to have the output "abcXX1234XXabc"  
With replacing by "XX$1XX" this works.  
However I want to use the named capture group. How can this be done?  
Using "XX$numberXX" leads to "abcXX$numberXXabc"

Thanks for your support in advance.

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### Author: ![michaelblight](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/michaelblight/32/445_2.png) [@michaelblight](https://discourse.nodered.org/u/michaelblight)
#### Post date: [9 June 2020 03:50 UTC](https://discourse.nodered.org/t/named-capture-groups-in-change-nodes-regex/28014/2 "2020-06-09T03:50:30Z")

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You forgot to name the capture group. Also, when using the named group, don't use parentheses (I think that is Perl).

So `(?[0-9]+)` should be `(?<number>[0-9]+)`  
And `XX${number}XX` should be `XX$<number>XX`

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<div class="post-metadata">

### Author: ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)
#### Post date: [23 June 2020 03:50 UTC](https://discourse.nodered.org/t/named-capture-groups-in-change-nodes-regex/28014/3 "2020-06-23T03:50:32Z")

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