类型错误：* 不支持的操作数类型：'NoneType' 和 'int'

Question

I couldn't find my mistake in this code below. If I say "return" instead of "print" in else part, code can not execute else part, it only makes calculations in if part. How can i fix this?

def calculatePerimeter(length, depth):
    if depth == 1:
        return 3 * length
    else:
        print (calculatePerimeter(length, depth-1) * (4/3)**(depth)) / ((4/3)**(depth-1))

calculatePerimeter(100, 3)

Answer 1

You need to return the value in the else clause, otherwise there's nothing to multiply (except when making the last call in the recursion). Then you need to call print when calling the function.

def calculatePerimeter(length, depth):
    if depth == 1:
        return 3 * length
    else:
        return (calculatePerimeter(length, depth-1) * (4/3)**(depth)) / ((4/3)**(depth-1))

print(calculatePerimeter(100, 3))