str.join 拼接字符串

字符串方法 str.join()，Python 官方文档描述如下：

help(str.join)

Help on method_descriptor:

join(self, iterable, /)
    Concatenate any number of strings.
    
    The string whose method is called is inserted in between each given string.
    The result is returned as a new string.
    
    Example: '.'.join(['ab', 'pq', 'rs']) -> 'ab.pq.rs'

返回一个由 iterable 中的字符串拼接而成的字符串。如果 iterable 中存在任何非字符串值则会引发 TypeError。调用该方法的字符串将作为元素之间的分隔。

'~'.join('abc')

'a~b~c'

'acb'.join(['1','2'])

'1acb2'

''.join(['1','2'])

'12'

'-'.join({'1':1,'2':2})

'1-2'

'-'.join(['1',2])

---------------------------------------------------------------------------

TypeError                                 Traceback (most recent call last)

<ipython-input-9-fc346e5ca62e> in <module>
----> 1 '-'.join(['1',2])


TypeError: sequence item 1: expected str instance, int found

'-'.join(b'abc')

---------------------------------------------------------------------------

TypeError                                 Traceback (most recent call last)

<ipython-input-8-9d04d7060926> in <module>
----> 1 '-'.join(b'abc')


TypeError: sequence item 0: expected str instance, int found