Python 如何创建空列表列表
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How to create a list of empty lists
提问by daemon_headmaster
Apologies if this has been answered before, but I couldn't find a similar question on here.
抱歉，如果之前已经回答过这个问题，但我在这里找不到类似的问题。
I am pretty new to Python and what I am trying to create is as follows:
我对 Python 很陌生，我要创建的内容如下：
list1 = []
list2 = []
results = [list1, list2]
This code works absolutely fine, but I was wondering if there was a quicker way to do this in one line.
这段代码工作得很好，但我想知道是否有一种更快的方法可以在一行中做到这一点。
I tried the following, which didn't work, but I hope it demonstrates the sort of thing that I'm after:
我尝试了以下操作，但没有用，但我希望它展示了我所追求的东西：
result = [list1[], list2[]]
Also, in terms of complexity, would having it on one line really make any difference? Or would it be three assignments in either case?
此外，就复杂性而言，将它放在一条线上真的会有什么不同吗？或者在任何一种情况下都是三个任务？
采纳答案by Dawny33
For manually creating a specified number of lists, this would be good:
对于手动创建指定数量的列表，这会很好：
empty_list = [ [], [], ..... ]
In case, you want to generate a bigger number of lists, then putting it inside a for loop would be good:
如果你想生成更多的列表，那么把它放在 for 循环中会很好：
empty_lists = [ [] for _ in range(n) ]
回答by dietbacon
If you want a one-liner you can just do:
如果你想要一个单线你可以这样做：
result = [[],[]]
回答by roeland
For arbitrary length lists, you can use [ [] for _ in range(N) ]
对于任意长度的列表，您可以使用 [ [] for _ in range(N) ]
Do notuse [ [] ] * N, as that will result in the list containing the same list objectNtimes
不要使用[ [] ] * N，因为这将导致列表包含相同的列表对象N时间
回答by Michael
results = [[],[]]
or
或者
results = [list(), list()]
回答by Sina Safarabadi
I would suggest using numpy because you can build higher-dimensional list of lists as well:
我建议使用 numpy，因为您也可以构建更高维的列表列表：
import numpy as np
LIST = np.zeros( [2,3] )# OR np.zeros( [2,3,6] )
It works in any number of dimensions.
它适用于任意数量的维度。
