Double THEN statement in IF

[DetlevD]

@thaw04

... When an artist already exists in my library i want to assign the genre for it i choose in the past, therefore i exported all my artists with their chosen genres ...
I tried something like this but probable the and function is not possible without an if?: ...

1. The functions "$and, $or, $eql, $not" etc. are boolean functions (see manual), ...
   that means, their result is only a invisible boolean value of "true" resp. "false".
   These functions are not able for connecting strings or other string manipulations.

2. I understand your problem this way, that you need a sort of lookup table, where you can search for a dedicated input value and find the related output value.

You can create such a lookup table as a simple text file, having two columns, the search column and the find column, e. g. ...
Artist|Genre
Jon Hopkins|Techno
Marisa Monte|Brasileira

Using Mp3tag Actions you can load this text file into a helper tag-field.
Then look for the search value in the helper tag-field, e. g. "Jon Hopkins", and extract the related find value "Techno".

See there ...
match some words from comment and put them in genre

In the past I did several attempts to do so within Mp3tag, you have to find them somewhere in the Forum.
https://www.google.de/search?q=site%3Aforum...+detlevd+lookup

@thaw04

... So this works but what to do with new artists? I thought of adding a characteristic to the genre tag or another field so afterwards i can filter them and only review the new artists. ...

The first step would be ... set a default value for the genre, like "---unknown---" or such, ...
then try to find the proper Artist, ...
then get the Artist related Genre value, ... and use it, ...
otherwise leave the genre tag-field as is or remove it.

@thaw04

...
I tried something like this but probable the and function is not possible without an if?:
$if($and($neql(%GENRE%,'Soundtrack'),$eql(%ARTIST%,'Jon Hopkins')),'Idm Ambient',%GENRE%)$and($replace,%GENRE%,%GENRE%),$replace(%LAND%,'(new)')))

See above post #2, last proposal.
If you want to change two different tag-fields, using the same condition, ...
then you have to apply two actions, one for each tag-field, using the same condition.

DD.20150118.1510.CET