递归思想实例

简述

代码实例

1)字母反转

#递归思想,递归向里面往外扩展呈现出来的也就是从里到外的
def func(str_num):
    if len(str_num) <1:
        return str_num
    return func(str_num[1:])+str_num[0]
result = func(str_num)
print result

2）快排

def kuaiPai(num):
    da,zhong,xiao = [],[],[]
    #如果没有条件条件限制会报错“IndexError: list index out of range”
    #新的递归da或xiao数组赋给num；
    #小于1说明是最后一次递归return num而不是最后一次递归的数据
    if len(num)<1:
        return num
    pivo = num[0]
    for i in range(len(num)):
        if num[i] > pivo:
            da.append(num[i])
        elif num[i] < pivo:
            xiao.append(num[i])
        else:
            zhong.append(num[i])
    less = kuaiPai(xiao)
    more = kuaiPai(da)
    return less+zhong+more
print(kuaiPai(num=[8,2,3,1,5,2]))