我有一个矩阵mat
:
array([[ 1, 2, 3, 4, 5],
[ 6, 7, 8, 9, 10],
[11, 12, 13, 14, 15],
[16, 17, 18, 19, 20],
[21, 22, 23, 24, 25]])
我想知道为什么 mat[:3,1:2]
是:
array([[ 2],
[ 7],
[12]])`
但是 mat[:3,1]
是:
array([ 2, 7, 12])
最佳答案
An integer,
i
, returns the same values asi:i+1
except the dimensionality of the returned object is reduced by1
. In particular, a selection tuple with thep-th
element an integer (and all other entries:
) returns the corresponding sub-array with dimensionN - 1
. IfN = 1
then the returned object is an array scalar. These objects are explained in Scalars. https://docs.scipy.org/doc/numpy-1.13.0/reference/arrays.indexing.html
谢谢@Kasramvd
关于python - Numpy 矩阵索引等价,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/49981791/