阶乘程序打印多个数字

Question

我正在学习Python，陷入阶乘程序中，我得到多行输出而不是单行输出。

我写的程序

num = int (input ("Enter a number: "))
factorial = 1

if num == 0:
    print ("The factorial of 0 is 1")
elif num <0:
    print ("Error, negative number does not have factorial")
else:
     for i in range (2, num +1):
            factorial = factorial*i
            print ("the factorial is: ", factorial)

得到如下输出。

Enter a number: 4
the factorial is:  2
the factorial is:  6
the factorial is:  24

我正在寻找单行答案，但得到多行答案，我无法理解为什么。

Answer 1

您不需要显式测试输入是否等于 0。通过仔细构建范围可以获得正确的结果。

不要打印循环内的中间值 - 只需在循环终止后打印一次。

使用 Python 3.8+ 你可以这样做：

if (n := int(input('Input value for n: '))) < 0:
    print('Unable to calculate factorial of a negative number')
else:
    f = 1
    for i in range(2, n+1):
        f *= i
    print(f'{n}! = {f}')

如果 n < 2 (but not negative) the loop will not be entered and so the value of 1 initially assigned to f 就是正确答案

Answer 2

因为你的输出有多个答案。而不是使用 while 范围。

num = int (input ("Enter a number: "))
factorial = 1
i=1
if num == 0:
    print ("The factorial of 0 is 1")
elif num <0:
    print ("Error, negative number does not have factorial")
else:
     while i<=num:
       factorial = factorial*i
       i=i+1
     print ("the factorial is: ", factorial)

或者，

num = int (input ("Enter a number: "))
factorial = 1

if num == 0:
    print ("The factorial of 0 is 1")
elif num <0:
    print ("Error, negative number does not have factorial")
else:
     for i in range (2, num +1):
            factorial = factorial*i
     print ("the factorial is: ", factorial)

有最简单的方法：

import math
num = int (input ("Enter a number: "))
if num == 0:
    print ("The factorial of 0 is 1")
elif num <0:
    print ("Error, negative number does not have factorial")
else:
     factorial=math.factorial(num)
     print ("the factorial is: ", factorial)

Answer 3

num = int(input("请输入一个数字：")) 阶乘 = 1

如果 num == 0: print("0的阶乘是1") elif 数字 <0: print ("Error, negative number does not have factorial") else: for i in range (2, num +1): factorial = factorial*i print ("the factorial is: ", factorial)

Answer 4

print ("the factorial is: ", factorial)

目前，您的 print 语句位于 for 循环的范围内，这就是为什么在每次迭代之后也会评估 print 语句。因此，为了避免这种情况，只需将 print 语句从 for 循环范围中移出

num = int (input ("Enter a number: "))
factorial = 1

if num == 0:
    print ("The factorial of 0 is 1")
elif num <0:
    print ("Error, negative number does not have factorial")
else:
     for i in range (2, num +1):
            factorial = factorial*i
print ("the factorial is: ", factorial)