# Prefix a field in logstash based on size/length of field
**URL:** https://discuss.elastic.co/t/prefix-a-field-in-logstash-based-on-size-length-of-field/56664
**Category:** Logstash
**Created:** [July 28, 2016, 7:18pm UTC](https://discuss.elastic.co/t/prefix-a-field-in-logstash-based-on-size-length-of-field/56664 "2016-07-28T19:18:59Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@nkapur](https://discuss.elastic.co/u/nkapur)
#### Post date: [July 28, 2016, 7:18pm UTC](https://discuss.elastic.co/t/prefix-a-field-in-logstash-based-on-size-length-of-field/56664/1 "2016-07-28T19:18:59Z")
Hello! I have a field (string) called clubcode. Valid incoming values are say, 014, 14, 22, 022, 111. I want to replace 14 with 014 and 22 with 022 so that I can aggregate using clubcode as term in Kibana. How do I achieve this in logstash i.e. prefix clubcode with a 0 if the incoming size of clubcode data is 2 digits. Thanks!
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 6, 2017, 4:46am UTC](https://discuss.elastic.co/t/prefix-a-field-in-logstash-based-on-size-length-of-field/56664/2 "2017-07-06T04:46:05Z")