循环嵌套 for循环

嵌套循环求排列

#双重
target = 'abc'
for x in target:
    for y in target:
        if x != y:
            print(x, y)

#多重
target = 'abc'
for x in target:
    for y in target:
        for z in target:
            if x!=y and x!=z and y!=z:
                print(x, y, z)

#递归嵌套
def abc_arrange(n, data):
    # 遍历abc
    for x in data:
        print(x)
 
    # 调用自己2次
    for i in range(n):
        abc_arrange(n-1, data) # 传入的参数为n-1为嵌套循环
 
n = 2 # 选2个进行组合
target = 'abc' # 组合为abc
abc_arrange(n, target)


def abc_arrange(n, data):
    if n == 0:
        return
 
    # 遍历abc
    for x in data:
        print(x)
        abc_arrange(n-1, data)
 
n = 2 # 选2个进行组合
target = 'abc' # 组合为abc
abc_arrange(n, target)