mxnet pick挑选

mx.symbol.slice_axis可以直接在某一维上切割，选择整行或整列。

pick 是精准挑选指定位置的值，

 

精准筛选指定位置的值。

代码格式，x,y都需要转成mxnet nd.array形式

import mxnet as mx
import mxnet.gluon.loss as gloss
#

from mxnet import nd

x =np.array([[ 1.,  2.],
     [ 3.,  4.],
     [ 5.,  6.]])

x = mx.nd.array(x)

y=np.array([ 0,  1,1])
y=mx.nd.array(y)
result= nd.pick(x, y,1)
print(result)

 

结果：

[1. 4. 6.]
<NDArray 3 @cpu(0)>

官方举例：

    Examples::

      x = [[ 1.,  2.],
           [ 3.,  4.],
           [ 5.,  6.]]

      // picks elements with specified indices along axis 0
      pick(x, y=[0,1], 0) = [ 1.,  4.]

      // picks elements with specified indices along axis 1
      pick(x, y=[0,1,0], 1) = [ 1.,  4.,  5.]

      y = [[ 1.],
           [ 0.],
           [ 2.]]

      // picks ele