python 指定长度指定类型的随机字符串，参数：长度、类型

python
import random


def rand_str(length=4, kind=0):
    if kind == 0:   # 纯数字
        base_str = '1234567890'
    elif kind == 1: # 纯字母
        base_str = 'qwertyuiopasdfghjklzxcvbnmQWERTYUIOPLKJHGFDSAZXVCBNM'
    else:
        base_str='qwertyuiopasdfghjklzxcvbnmQWERTYUIOPLKJHGFDSAZXVCBNM1234567890'

    return ''.join(random.choice(base_str) for i in range(length))


print(rand_str(4,1))