Multiply an input by 5 raised to the number of digits of each numbers, but my code needs reworking

Question

I'm trying to multiply an input * 5 raised to the power of the input. I tried this:

def multiply(n):
return 5 ** len(str(n)) * n

I tried (n = -2), but instead of giving me -10, which is the correct answer, it gave me -50 Why doesn't this output the correct numbers when n is negative?

Answer 1

you are directly checking the length of your input by casting it to string:

>>> n = -2
>>> str(n)
'-2' # String with length of two -> '-' and '2' (string 2)
>>> len(str(n))
2

Maybe you can try this (not sure if it's good or bad, but will work as you expected):

# The dirty way.. 

def multiply(num: int):
    # Initialize a variable to keep track of length
    length = 0
    
    # Convert the input to string and iterate over it
    for n in str(num):

        # If the current character is int, increment the length variable
        try:
            if isinstance(int(n), int):
                length += 1

        # Above code will raise error for '-', catch here
        except ValueError:
            pass

    return 5 ** length * num

# Try with the input -2 again
print(multiply(-2))