# Adding leading zeros to an extended field

**URL:** https://community.mp3tag.de/t/adding-leading-zeros-to-an-extended-field/8769
**Category:** Support
**Created:** [August 13, 2009, 9:34am UTC](https://community.mp3tag.de/t/adding-leading-zeros-to-an-extended-field/8769 "2009-08-13T09:34:16Z")
**Posts on this page:** 1
**Showing post:** 2

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### Author: ![dano](https://community.mp3tag.de/user_avatar/community.mp3tag.de/dano/32/6_2.png) [@dano](https://community.mp3tag.de/u/dano)
#### Post date: [August 13, 2009, 3:45pm UTC](https://community.mp3tag.de/t/adding-leading-zeros-to-an-extended-field/8769/2 "2009-08-13T15:45:51Z")

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Make a [new action](https://community.mp3tag.de/t/967/1)

1. 

_Action type:_ **Replace with regular expressions**  
_Field:_ **INITIALKEY**  
_Regular expression:_ **^(\d[^\d])**  
_Replace matches with:_ **0$1**

1. 

_Action type:_ **Format value**  
_Field:_ **CONTENTGROUP**  
_Format string:_ **%INITIALKEY%**

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_[View the full topic](https://community.mp3tag.de/t/adding-leading-zeros-to-an-extended-field/8769)._