使用Scala在Breeze中使用矩阵行操作？

Question

I've a DenseMatrix 我有一个DenseMatrix

1  2  3  0   0   0   0    0    0    
0  0  0  11  22  33  0    0    0    
0  0  0  0   0   0   111  222  333

I want to remove the first row and then a last row with all 0 s 我想删除第一行，然后删除所有0秒的最后一行

0  0  0  11  22  33  0    0    0    
0  0  0  0   0   0   111  222  333 
0  0  0  0   0   0   0    0    0

How do I achieve this in Breeze ? 我如何在微风中实现这一目标？

Answer 1

First, gather the rows you still want: 首先，收集您仍想要的行：

val subset = matrix(::, 2 to 3)

then add the zeroes: 然后添加零：

val newMatrix = DenseMatrix.horzcat(subset, DenseMatrix.zeros[Double](1,9))

I might have mixed up rows and columns in the last line. 我可能在最后一行混淆了行和列。