Python 如何从字符串中提取第一个和最后一个单词？
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How to extract the first and final words from a string?
提问by Lior Dahan
I have a small problem with something I need to do in school...
我在学校需要做的事情有一个小问题......
My task is the get a raw input string from a user (text = raw_input())
and I need to print the first and final words of that string.
我的任务是从用户 ( text = raw_input())获取原始输入字符串，我需要打印该字符串的第一个和最后一个单词。
Can someone help me with that? I have been looking for an answer all day...
有人可以帮我吗？我一整天都在寻找答案......
回答by Moinuddin Quadri
You have to firstly convert the string to listof words using str.splitand then you may access it like:
您必须首先使用将字符串转换list为单词str.split，然后您可以像这样访问它：
>>> my_str = "Hello SO user, How are you"
>>> word_list = my_str.split() # list of words
# first word v v last word
>>> word_list[0], word_list[-1]
('Hello', 'you')
From Python 3.x, you may simply do:
从 Python 3.x 开始，您可以简单地执行以下操作：
>>> first, *middle, last = my_str.split()
回答by Anand Chitipothu
If you are using Python 3, you can do this:
如果您使用的是 Python 3，您可以这样做：
text = input()
first, *middle, last = text.split()
print(first, last)
All the words except the first and last will go into the variable middle.
除了 first 和 last 之外的所有单词都将进入变量middle。
回答by toom
Let's say xis your input. Then you may do:
假设x是您的输入。那么你可以这样做：
x.partition(' ')[0]
x.partition(' ')[-1]
回答by Mike
You would do:
你会这样做：
print text.split()[0], text.split()[-1]
回答by quapka
Some might say, there is never too many answer's using regular expressions (in this case, this looks like the worst solutions..):
有人可能会说，使用正则表达式的答案永远不会太多（在这种情况下，这看起来是最糟糕的解决方案..）：
>>> import re
>>> string = "Hello SO user, How are you"
>>> matches = re.findall(r'^\w+|\w+$', string)
>>> print(matches)
['Hello', 'you']
回答by Cybernetic
Simply pass your string into the following function:
只需将您的字符串传递给以下函数：
def first_and_final(str):
res = str.split(' ')
fir = res[0]
fin = res[len(res)-1]
return([fir, fin])
Usage:
用法：
first_and_final('This is a sentence with a first and final word.')
Result:
结果：
['This', 'word.']
