# Parsing underscore
**URL:** https://discuss.elastic.co/t/parsing-underscore/253104
**Category:** Logstash
**Created:** [October 23, 2020, 9:10am UTC](https://discuss.elastic.co/t/parsing-underscore/253104 "2020-10-23T09:10:19Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@rbeg](https://discuss.elastic.co/u/rbeg)
#### Post date: [October 23, 2020, 9:10am UTC](https://discuss.elastic.co/t/parsing-underscore/253104/1 "2020-10-23T09:10:19Z")
Hello,
Can you help me please?
I need to parse this field in logstash filter :
word1\_word2\_word3\_word4
And I want to put word3 into a new field named my\_field.
How to do this please?
I try with grok and regular expression.
Thanks
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### Author:  [@Wolfram\_Haussig](https://discuss.elastic.co/u/Wolfram_Haussig)
#### Post date: [October 23, 2020, 10:06am UTC](https://discuss.elastic.co/t/parsing-underscore/253104/2 "2020-10-23T10:06:45Z")
Hello Regis,
Can you post us which grok you have tried? Maybe we can help you with finding the error.
Best regards
Wolfram
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### Author:  [@rbeg](https://discuss.elastic.co/u/rbeg)
#### Post date: [October 23, 2020, 1:58pm UTC](https://discuss.elastic.co/t/parsing-underscore/253104/3 "2020-10-23T13:58:48Z")
I found a solution with this :
([0-9a-zA-Z]_)(\_)([0-9a-zA-Z]_)(\_)(?\[0-9a-zA-Z]\*)
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [November 20, 2020, 1:58pm UTC](https://discuss.elastic.co/t/parsing-underscore/253104/4 "2020-11-20T13:58:55Z")
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