如何在Python中使用MATLAB的唯一值(a，'rows')? [英] How can I use the unique(a, 'rows') from MATLAB in Python?

问题描述

我正在将一些东西从MATLAB转换为Python语言.

I'm translating some stuff from MATLAB to the Python language.

在 NumPy 中有一个唯一的命令.但是由于MATLAB程序也运行行"命令，所以它提供了一些不同的地方.

There's this command, unique(a), in NumPy. But since the MATLAB program runs the 'rows' command also, it gives something a little different.

Python中是否有类似的命令，或者我应该做一些能做同样事情的算法?

Is there a similar command in Python or should I make some algorithm that does the same thing?

推荐答案

假设您的2D数组以通常的C顺序存储(也就是说，每一行都被视为主数组中的一个数组或列表；换句话说，行优先顺序)，或者事先转置数组，否则，您可以执行类似...

Assuming your 2D array is stored in the usual C order (that is, each row is counted as an array or list within the main array; in other words, row-major order), or that you transpose the array beforehand otherwise, you could do something like...

>>> import numpy as np
>>> a = np.array([[1, 2, 3], [2, 3, 4], [1, 2, 3], [3, 4, 5]])
>>> a
array([[1, 2, 3],
       [2, 3, 4],
       [1, 2, 3],
       [3, 4, 5]])
>>> np.array([np.array(x) for x in set(tuple(x) for x in a)]) # or "list(x) for x in set[...]"
array([[3, 4, 5],
       [2, 3, 4],
       [1, 2, 3]])

当然，如果您需要按其原始顺序排列唯一行，那么这实际上是行不通的.

Of course, this doesn't really work if you need the unique rows in their original order.

顺便说一句，要模拟类似unique(a, 'columns')的内容，您只需转置原始数组，执行上面显示的步骤，然后再转回.

By the way, to emulate something like unique(a, 'columns'), you'd just transpose the original array, do the step shown above, and then transpose back.

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