Python finds the factorial of n

Factorial is an arithmetic symbol invented by Christian Kramp (1760-1826) in 1808. It is a mathematical term. The factorial of a positive integer is the product of all positive integers less than or equal to that number, and the factorial of 0 is 1. The factorial of a natural number n is written n!.

Let’s take a look at how to use Python to calculate the factorial of n:

The first one: use the functools tool to process

import functools
result = (lambda k: functools.reduce(int.__mul__, range(1, k + 1), 1))(5)
print(result)```

The second one: ordinary loops

x = 1
y = int(input("请输入要计算的数:"))
for i in range(1, y + 1):
   x = x * i
print(x)

The third way: using recursion

def func(n):
    if n == 0 or n == 1:
        return 1
    else:
        return (n * func(n - 1))
 a = func(5)
 print(a)

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