函数递归

函数递归：函数重复地调用自己，这叫递归。

# 函数不断地内部调用
def d():
    return '232'
 
def c():
    r = d()
    return r
 
def b():
    r = c()
    return r
 
def a():
    r = b()
    print(r)
a()
 
-----
232

#函数重复调用自己，叫做递归
def func(n):
    n +=1
    if n >= 5:
        return 'a'
    return func(n)
 
r = func(1)
print(r)
 
-----
a

使用递归 7*6*5*4*3*2*1
1
2
3
4
5
6
7
8
9
10
11
12
#方法一
def factorial(num):

    if num>1:
        return num*factorial(num-1)
    else:
        return 1

sum =factorial(7)
print(sum)
------
5040

阶乘变换（11*9*7*5*3*1）(12*10*8*6*4*2)

def fa1(a):
 
    if a%2 == 0:
        if a > 2:
            return a*fa1(a-2)
        else:
            return 2
        pass
    else:
        if a > 1:
            return a*fa1(a-2)
        else:
            return 1
 
b = fa1(11)
c = fa1(12)
print(b,c)
-----
10395 46080

来自为知笔记(Wiz)