def generate_random_str(randomlength=16):
  """
  生成一个指定长度的随机字符串
  """
  random_str = ''
  base_str = 'ABCDEFGHIGKLMNOPQRSTUVWXYZabcdefghigklmnopqrstuvwxyz0123456789'
  length = len(base_str) - 1
  for i in range(randomlength):
    random_str += base_str[random.randint(0, length)]
  return random_str

f = generate_random_str(24)
print (f)

import random
import string

def generate_random_str(randomlength=16):
  """
  生成一个指定长度的随机字符串，其中
  string.digits=0123456789
  string.ascii_letters=abcdefghigklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ
  """
  str_list = [random.choice(string.digits + string.ascii_letters) for i in range(randomlength)]
  random_str = ''.join(str_list)
  return random_str

f = generate_random_str(24)
print (f)