R行乘法 – restyle?

参见英文答案 > Multiply rows of matrix by vector?                                    4个
如果我有一个(批量x 5)矩阵和一个(1 x 5)矩阵,有没有比这更好的方法将它们乘以行:

> q 
     [,1] [,2] [,3] [,4] [,5]
[1,]    1    2    3    4    5

> z
     [,1] [,2] [,3] [,4] [,5]
[1,]    1    6   11   16   21
[2,]    2    7   12   17   22
[3,]    3    8   13   18   23
[4,]    4    9   14   19   24
[5,]    5   10   15   20   25

> t(apply(z,1,function (x) {x*q})) 
     [,1] [,2] [,3] [,4] [,5]
[1,]    1   12   33   64  105
[2,]    2   14   36   68  110
[3,]    3   16   39   72  115
[4,]    4   18   42   76  120
[5,]    5   20   45   80  125

这有效,但似乎很糟糕.有没有我失踪的功能?

最佳答案
另一个选择是扫描

sweep(z, 2, q, "*")
#      [,1] [,2] [,3] [,4] [,5]
# [1,]    1   12   33   64  105
# [2,]    2   14   36   68  110
# [3,]    3   16   39   72  115
# [4,]    4   18   42   76  120
# [5,]    5   20   45   80  125

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