向量和矩阵之间的自动乘法(Automatic multiplication between vector and matrix)

向量和矩阵之间的自动乘法(Automatic multiplication between vector and matrix)

我有这个R代码：

> coef [1] 1.5 2.4 3.9 4.4 > y [,1] [,2] [,3] [,4] [1,] 1 2 12 45 [2,] 5 6 7 8 [3,] 9 10 2 12 [4,] 13 14 15 45 [5,] 17 18 39 7

我必须将列的每个值与相应的系数相乘。 结果应该是：

First column: 1*1.5 5*1.5 9*1.5 13*1.5 17*1.5 Second column: 2*2.4 6*2.4 10*2.4 14*2.4 18*2.4 Third column: 12*3.9 7*3.9 2*3.9 15*3.9 39*3.9 Fourth column: 45*4.4 8*4.4 12*4.4 45*4.4 7*4.4

所有列的值在矢量中的相同索引处由相同的系数模拟。

我怎样才能做这个计算？

解决方案可以是：

> y[,1] <- y[,1] * coef[1] > y[,2] <- y[,2] * coef[2] > y[,3] <- y[,3] * coef[3] > y[,4] <- y[,4] * coef[4]

但似乎没有太优化！ 更好的东西？

谢谢！

I have this R code:

> coef [1] 1.5 2.4 3.9 4.4 > y [,1] [,2] [,3] [,4] [1,] 1 2 12 45 [2,] 5 6 7 8 [3,] 9 10 2 12 [4,] 13 14 15 45 [5,] 17 18 39 7

I have to multiply each value of the column with the respective coef. The result should be:

First column: 1*1.5 5*1.5 9*1.5 13*1.5 17*1.5 Second column: 2*2.4 6*2.4 10*2.4 14*2.4 18*2.4 Third column: 12*3.9 7*3.9 2*3.9 15*3.9 39*3.9 Fourth column: 45*4.4 8*4.4 12*4.4 45*4.4 7*4.4

All the column's values moltiplied by the same coefficient at the same index in the vector.

How can I do this calculation?

The solution could be:

> y[,1] <- y[,1] * coef[1] > y[,2] <- y[,2] * coef[2] > y[,3] <- y[,3] * coef[3] > y[,4] <- y[,4] * coef[4]

But doesn't seem too optimized! Something better?

Thank you!

最满意答案

这会给你你想要的东西：

t( t(y) * coef )

This will give you what you want:

t( t(y) * coef )