I'm trying to format a simple text string to add a couple of hyphens. The text string is an 11 digit number so the outcome should look like this: 2013-50-12345. I tried the following calculation:
Let ( field = filter ( field ; "0123456789" ) ; Left(field;4) & "-" & Middle(field;5;2) & "-" & Right(field;5)
This works just fine if the "Do not replace existing value..." is not selected. I don't want to replace existing values, but when I select this option the calculation no longer works. Any ideas?