如何在numpy数组列中找到最大值? [英] How to find max value in a numpy array column?

问题描述

我可以找到这个问题的很多排列，但不是这个(相当简单)的排列:如何找到numpy数组的特定列的最大值(以最pythonic的方式)?

I can find quite a few permutations of this question, but not this (rather simple) one: how do I find the maximum value of a specific column of a numpy array (in the most pythonic way)?

a = array([[10, 2], [3, 4], [5, 6]])

我想要的是第一列和第二列的最大值(这些是x，y坐标，我最终需要每种形状的高度和宽度)，因此max x坐标是10，max y坐标是6.

What I want is the max value in the first column and second column (these are x,y coordinates and I eventually need the height and width of each shape), so max x coordinate is 10 and max y coordinate is 6.

我尝试过:

xmax = numpy.amax(a,axis=0)
ymax = numpy.amax(a,axis=1)

但是这些产量

array([10, 6])
array([10, 4, 6])

...不是我所期望的.

...not what I expected.

我的解决方案是使用切片:

My solution is to use slices:

xmax = numpy.max(a[:,0])
ymax = numpy.max(a[:,1])

哪种方法可行，但似乎并不是最好的方法.

Which works but doesn't seem to the best approach.

建议?

推荐答案

只需解压缩列表:

In [273]: xmax, ymax = a.max(axis=0)

In [274]: print xmax, ymax
#10 6

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