Regex: How to match a string that is not only numbers

Question

Is it possible to write a regular expression that matches all strings that does not only contain numbers? If we have these strings:

• abc

Answer 1

.*[^0-9]{1,}.*

Works fine for us.

We want to use the used answer, but it's not working within YANG model.

And the one I provided here is easy to understand and it's clear: start and end could be any chars, but, but there must be at least one NON NUMERICAL characters, which is greatest.