python - 制作一个 numpy 零数组，其中每行有 8 个零，对应于输出的索引更改为 1

Question

我想创建一个 numpy 零数组：

Y_numpy = [[0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0],
...]

我有：

Y = [1,2,7,8,3,4,6,7,8,8,8,8,8,4,4,4,6,3,2,3,4,5,6,7,...]

我的目标是将索引处的值更改为 Y_numpy 中的“1”，这与每个 Y 的值相同。

例如：

Y[0] = 1 => Y_numpy[0] = [1,0,0,0,0,0,0,0]
Y[1] = 2 => Y_numpy[1] = [0,1,0,0,0,0,0,0]
Y[2] = 7 => Y_numpy[2] = [0,0,0,0,0,0,1,0]
Y[3] = 8 => Y_numpy[3] = [0,0,0,0,0,0,0,1]
Y[4] = 3 => Y_numpy[4] = [0,0,1,0,0,0,0,0]
Y[5] = 4 => Y_numpy[5] = [0,0,0,1,0,0,0,0]
...

如果您需要任何其他信息或更多解释，请告诉我。

标签： pythonnumpy

Answer 1

In [179]: Y = [1,2,7,8,3,4,6,7,8,8,8,8,8,4,4,4,6,3,2,3,4,5,6,7]                 
In [180]: len(Y)                                                                
Out[180]: 24
In [181]: Ynum = np.zeros((24,8),int) 

二维数组赋值；每行一个值：

In [184]: Ynum[np.arange(24),np.array(Y)-1] = 1                                 
In [185]: Ynum[:6,:]                                                            
Out[185]: 
array([[1, 0, 0, 0, 0, 0, 0, 0],
       [0, 1, 0, 0, 0, 0, 0, 0],
       [0, 0, 0, 0, 0, 0, 1, 0],
       [0, 0, 0, 0, 0, 0, 0, 1],
       [0, 0, 1, 0, 0, 0, 0, 0],
       [0, 0, 0, 1, 0, 0, 0, 0]])