how to write a function to return -1 if string is not found in matlab??

I wrote a function that finds a 3 digit number of a filename? i need to write an if statement to return -1 if this part of the file cannot be extracted ? how do i do that?

Thanks :)

[the cyclist]

There are several possible ways to do this. Can you post your code, or at least the part of it that attempts the extraction?

[Image Analyst]

ANY 3 digit number whatsoever, or only a specific 3 digit number that you specify in the input argument list along with the filename?

Answer 1

[the cyclist]

if isempty(w)
    w = -1;
end