# What is the constant of blank?
**URL:** https://community.mp3tag.de/t/what-is-the-constant-of-blank/63744
**Category:** Support
**Created:** [February 12, 2024, 6:34am UTC](https://community.mp3tag.de/t/what-is-the-constant-of-blank/63744 "2024-02-12T06:34:04Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@henryking](https://community.mp3tag.de/u/henryking)
#### Post date: [February 12, 2024, 6:34am UTC](https://community.mp3tag.de/t/what-is-the-constant-of-blank/63744/1 "2024-02-12T06:34:04Z")
What is the constant of blank? For using in Action Replace.
for exsample
%GENRE%
original: null or empty field (constant of blank used here)
replace to: Pop
---
### Author:  [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)
#### Post date: [February 12, 2024, 6:36am UTC](https://community.mp3tag.de/t/what-is-the-constant-of-blank/63744/2 "2024-02-12T06:36:45Z")
As there are no empty fields - if data is not set for a field then it does not exist - use an action of the type "Format value" (in this case for GENRE) to fill a field with data.
---
### Author:  [@henryking](https://community.mp3tag.de/u/henryking)
#### Post date: [February 12, 2024, 6:48am UTC](https://community.mp3tag.de/t/what-is-the-constant-of-blank/63744/3 "2024-02-12T06:48:43Z")
OK, get it, 😍 many thanks 😄 🙂
---
### Author:  [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [February 12, 2024, 4:16pm UTC](https://community.mp3tag.de/t/what-is-the-constant-of-blank/63744/4 "2024-02-12T16:16:47Z")
If you want to reuse existing genres and only add `Pop` for empty/non-existing genres, you can use
`$if2(%genre%,Pop)`
as format string — or use the Filter before applying the action.
---
### Author:  [@system](https://community.mp3tag.de/u/system)
#### Post date: [March 13, 2024, 4:17pm UTC](https://community.mp3tag.de/t/what-is-the-constant-of-blank/63744/5 "2024-03-13T16:17:13Z")
This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.