我对如何使用分裂函数有疑问
str = James;Joseph;Arun;
str.split( ; )
我拿到了结果[James, Joseph, Arun,] [James, Joseph, Arun, ]
我需要输出为 [James, Joseph, Arun]
最好的办法是什么?
要删除所有空字符串, 您可以使用列表理解 :
>>> [x for x in my_str.split( ; ) if x]
或过滤器/火药把戏:
>>> filter(bool, my_str.split( ; ))
请注意, 这还将删除列表开头或中间的空字符串, 而不是最后的空字符串 。
如果您只想删除结尾处的空字符串, 您可以在拆分前先使用 > rstrip 。
>>> my_str.rstrip( ; ).split( ; )
首先从字符串右边缘删除 ; :
s.rstrip( ; ).split( ; )
您也可以使用 filter () () (它也会过滤在字符串结尾处找不到的空元素) 。 但是,在我看来,以上确实是最清洁的方法, 当您想要在结尾处避免空元素时, 因为字符串结尾处出现“ < code > ; ” 字符, 结果是“ < code > ; ” 。
<强度 > EDIT :实际上比上述方法(上述方法仍比使用 filter () () < () )更准确,是以下方法:
(s[:-1] if s.endswith( ; ) else s).split( ; )
这将只删除最后一个元素, 并且只有在该元素被创建为空时才能删除 。
测试所有三种解决方案,你会看到, 它们产生不同的结果:
>>> def test_solution(solution):
cases = [
James;Joseph;Arun; ,
James;;Arun ,
James;Joseph;Arun ,
;James;Joseph;Arun ,
James;Joseph;;; ,
;;; ,
]
for case in cases:
print %r => %r % (case, solution(case))
>>> test_solution(lambda s: s.split( ; )) # original solution
James;Joseph;Arun; => [ James , Joseph , Arun , ]
James;;Arun => [ James , , Arun ]
James;Joseph;Arun => [ James , Joseph , Arun ]
;James;Joseph;Arun => [ , James , Joseph , Arun ]
James;Joseph;;; => [ James , Joseph , , , ]
;;; => [ , , , ]
>>> test_solution(lambda s: filter(bool, s.split( ; )))
James;Joseph;Arun; => [ James , Joseph , Arun ]
James;;Arun => [ James , Arun ]
James;Joseph;Arun => [ James , Joseph , Arun ]
;James;Joseph;Arun => [ James , Joseph , Arun ]
James;Joseph;;; => [ James , Joseph ]
;;; => []
>>> test_solution(lambda s: s.rstrip( ; ).split( ; ))
James;Joseph;Arun; => [ James , Joseph , Arun ]
James;;Arun => [ James , , Arun ]
James;Joseph;Arun => [ James , Joseph , Arun ]
;James;Joseph;Arun => [ , James , Joseph , Arun ]
James;Joseph;;; => [ James , Joseph ]
;;; => [ ]
>>> test_solution(lambda s: (s[:-1] if s.endswith( ; ) else s).split( ; ))
James;Joseph;Arun; => [ James , Joseph , Arun ]
James;;Arun => [ James , , Arun ]
James;Joseph;Arun => [ James , Joseph , Arun ]
;James;Joseph;Arun => [ , James , Joseph , Arun ]
James;Joseph;;; => [ James , Joseph , , ]
;;; => [ , , ]
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