python - 类型错误 : can only concatenate str (not "int") to str SUM

Question

我正在尝试编写一个程序，将数字的立方求和到上限。

数学公式为(n*(n+1)/2)^2

我的Python代码:

def cube_numbers():
   upper_boundary = 0
   cube_sum = 0
   upper_boundary = input("Please enter the upper boundary:")
   cube_sum = ((upper_boundary * (upper_boundary + 1) / 2)**2)
   print("The sum of the cube of numbers up to" & upper_boundary & "is" & cube_sum)
#main
cube_numbers()

但是我收到以下错误:

  Traceback (most recent call last):

  File "C:/Users/barki/Desktop/sum of cubes.py", line 10, in <module>
    cube_numbers()

  File "C:/Users/barki/Desktop/sum of cubes.py", line 5, in cube_numbers
    cube_sum = ((upper_boundary * (upper_boundary + 1) / 2)**2)
TypeError: can only concatenate str (not "int") to str

Answer 1

您的函数的目的不应该是打印。此外，最好将输入提示移出函数，然后将该值传递到函数中。然后我们可以做的是获取 upper_boundary 作为 int 的输入，然后将其传递给 cube_numbers。该返回值现在将为 cube_sum，我们可以使用格式化打印来打印该语句。

def cube_numbers(x):
    y = int(((x * (x + 1) / 2)**2))
    return y

upper_boundary = int(input("Please enter the upper boundary: "))
cube_sum = cube_numbers(upper_boundary)

print('The sum of the cube of numbers up to {} is {}.'.format(upper_boundary, cube_sum))
# The sum of the cube of numbers up to 10 is 3025.