字符串等长分割

In [43]: s = 'axxxxxxxxxxxxxxxxxxxxxxxxxxxxx'

In [44]: [s[idx:idx+4] for idx in range(len(s)) if idx%4==0]
Out[44]: ['axxx', 'xxxx', 'xxxx', 'xxxx', 'xxxx', 'xxxx', 'xxxx', 'xx']

　　如果有其他字符，那么就都转成unicode，然后在分割。

In [1]: s = "axxxxxxxxxxxxxxxxxxxxxxxxxxx"

In [2]: [s[i:i+4] for i in range(0, len(s), 4)]
Out[2]: ['axxx', 'xxxx', 'xxxx', 'xxxx', 'xxxx', 'xxxx', 'xxxx']