# Preventing empty output lines in export **URL:** \ **Category:** Support\ **Created:** [March 13, 2016, 9:27pm UTC](https://community.mp3tag.de/t/preventing-empty-output-lines-in-export/17746 "2016-03-13T21:27:45Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![just\_Addict](https://community.mp3tag.de/letter_avatar_proxy/v4/letter/j/a9adbd/32.png) [@just\_Addict](https://community.mp3tag.de/u/just_Addict)\ **Post date:** [March 13, 2016, 9:27pm UTC](https://community.mp3tag.de/t/preventing-empty-output-lines-in-export/17746/1 "2016-03-13T21:27:45Z")
I've defined an mte export and read in the online help and also observed this in action that if you enclose a tag frame variable within right-angled brackets '[' and ']', it will not generate blank output if there is no value for the given tag frame variable. However, I wanted to get some control over the 'no value' bit by using an $if formula to possibly check for an alternate source being present and fallback on a 'no value' in case the alternate contains the same value (e.g. Album Artist vs Track Artist, i.e. %albumartist% and %artist% To my surprise the suppression of blank output then fails and outputs the line as if a value was present used formula format (generalized for simplicity, which does exact same in practice) is ``` [ PERFORMER "$if(%albumartist%,%artist%,)"] ``` the below however does work and suppresses the line completely if no value is present. ``` [ PERFORMER "%artist%"] ``` I would however like to use the top example as this allows me the flexibility to not include that line if it is the same as the already exported %albumartist% line defined earlier in the export. The bottom version only allows me to either generate a lot of lines with redundant values or skip them when no value is present. ---
**Author:** ![DetlevD](https://community.mp3tag.de/user_avatar/community.mp3tag.de/detlevd/32/123_2.png) [@DetlevD](https://community.mp3tag.de/u/DetlevD)\ **Post date:** [March 14, 2016, 8:12am UTC](https://community.mp3tag.de/t/preventing-empty-output-lines-in-export/17746/2 "2016-03-14T08:12:32Z")
> [@just\_Addict](#): > > I've defined an mte export and read in the online help and also observed this in action that if you enclose a tag frame variable within right-angled brackets '[' and ']', it will not generate blank output if there is no value for the given tag frame variable. ... > To my surprise the suppression of blank output then fails and outputs the line as if a value was present ... Yes, in Mp3tag scripting language the [...] square bracket clamp is an operator. Once there is any tagfield content operator within the square bracket clamp, e. g. %TITLE%, which owns a value, then the entire content of the square bracket clamp will be come into usage. This scripting line ... **[PERFORMER "$if(%ALBUMARTIST%,%ARTIST%,)"]** ... or written as ... **['PERFORMER "'$if(%ALBUMARTIST%,%ARTIST%,)'"']** ... has the meaning of ... "If ALBUMARTIST exists, then write ARTIST, else write nothing." If ALBUMARTIST does not exist, but ARTIST exist, then the result is the text: **'PERFORMER ""'** Probably you want this expression ... **['PERFORMER "'$if2(%ALBUMARTIST%,%ARTIST%)'"']** ... with the meaning of ... "If both tagfields do not exist, then the result is an empty string." DD.20160314.1042.CET ---
**Author:** ![system](https://community.mp3tag.de/uploads/default/original/2X/c/ce7035d426cb755a7916793326d23b465222a407.png) [@system](https://community.mp3tag.de/u/system)\ **Post date:** [February 9, 2026, 12:26pm UTC](https://community.mp3tag.de/t/preventing-empty-output-lines-in-export/17746/3 "2026-02-09T12:26:08Z")