[英]Python Tuple Unpacking
If I have 如果我有
nums_and_words = [(1, 'one'), (2, 'two'), (3, 'three')]
and would like 并希望
nums = [1, 2, 3]
words= ['one', 'two', 'three']
How would I do that in a Pythonic way? 我怎么用Pythonic方式做到这一点? It took me a minute to realize why the following doesn't work
我花了一分钟才意识到为什么以下不起作用
nums, words = [(el[0], el[1]) for el in nums_and_words]
I'm curious if someone can provide a similar manner of achieving the result I'm looking for. 我很好奇是否有人可以提供类似的方式来实现我正在寻找的结果。
Use zip
, then unpack: 使用
zip
,然后解压缩:
nums_and_words = [(1, 'one'), (2, 'two'), (3, 'three')]
nums, words = zip(*nums_and_words)
Actually, this "unpacks" twice: First, when you pass the list of lists to zip
with *
, then when you distribute the result to the two variables. 实际上,这两次“解压缩”:首先,当您将列表列表传递给
zip
带*
,然后将结果分发给两个变量。
You can think of zip(*list_of_lists)
as 'transposing' the argument: 您可以将
zip(*list_of_lists)
视为“转置”参数:
zip(*[(1, 'one'), (2, 'two'), (3, 'three')])
== zip( (1, 'one'), (2, 'two'), (3, 'three') )
== [(1, 2, 3), ('one', 'two', 'three')]
Note that this will give you tuples; 请注意,这将为您提供元组; if you really need lists, you'd have to
map
the result: 如果你真的需要列表,你必须
map
结果:
nums, words = map(list, zip(*nums_and_words))
nums = [nums_and_words[x][0] for x in xrange(len(nums_and_words)) ]
words = [nums_and_words[x][1] for x in xrange(len(nums_and_words)) ]
Testing if this works
print nums ,'&', words
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