>>> s=‘spam‘
>>> s=s.replace(‘m‘,‘111‘)
>>> s
‘spa111‘
>>> where=s.find(‘11‘)
>>> where
3
>>> s=s[:where]+‘eggs‘+s[(where+2):]
>>> s
‘spaeggs1‘
>>> L=list(s)
>>> L
[‘s‘, ‘p‘, ‘a‘, ‘e‘, ‘g‘, ‘g‘, ‘s‘, ‘1‘]
>>> s=‘‘.join(L) #把对象插入到join的参数内，插入位置为参数内分隔符的位置,以对象作为分隔符
>>> s
‘spaeggs1‘
>>> ‘spam‘.join([‘aaa‘,‘bbb‘,‘ccc‘,]) #S.join(iterable) -> str Return a string which is the concatenation of the strings in the iterable. The separator between elements is S.
‘aaaspambbbspamccc‘