python中拆分和拼接字符串

>>> a = "2018:03:15"
>>> a
‘2018:03:15‘
>>> a.split(sep = ":")    ## sep指定拆分的分隔符
[‘2018‘, ‘03‘, ‘15‘]

>>> a = ["aaa","bbb","ccc","ddd"]
>>> "_".join(a)   ## 指定连接符
‘aaa_bbb_ccc_ddd‘
>>> "===".join(a)
‘aaa===bbb===ccc===ddd‘
>>> b = ("aaa","bbb","ccc")
>>> type(b) 
<class ‘tuple‘>
>>> "-".join(b)    ## 拼接适用于一切可迭代对象
‘aaa-bbb-ccc‘