Help change from a while loop to a for loop

[captwiggum]

Larz's explanation is the best. As for my suggestion, here's what I had in mind:

def displayDigits(number):
    for x in range(number):
        divisor = 10 ** x

        if number // divisor == 0:
            return x

    return -1 # In case the number is magically too large

print(displayDigits(26))

Thank you!