Dear fellows,
I'm looking for a regex-pattern, which should not match, when a certain pattern (separator (underscore or minus) followed by number followed by any string) occurs within a string: I tried several variations with Positive and Negative Lookahead, but haven't found any regex yet which fullfills my needs
Any helps welcome - TIA
Edit: What I hoped to work was: 
\A([A-Za-z1-9\.-_]*)(?:(?![-_]\d).)

[download]
... but this also fails
Edit2: Sorry, my specification was not complete (see last example) - Extended specification: Strings starting with a number should not be matched as well

In reply to Regex pattern that fails when string contains a certain pattern by hoppfrosch

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