check the length of formula1 before doing the calculation like

Hello everybody,

I need someone's help.
I have the same error.

I have a field which is number but combine with string - (lets say "500 km" for example).
I need to remove the 'km' part of it and to stay only number - 500.

This happen with:
tonumber (mid ({Command.string_field},1,(INSTR({Command.string_field}, "km")-1)))

But when i try to export it in pdf it gives me this error message - "string length is less than 0 or not an integer". I already the previous suggestion to the problem but it's not working to men.

Any other ideas??

Edited by Leti - 19 Oct 2015 at 2:57am