r - R %*% 运算符

Question

这是什么？我无法通过使用 ? 获得帮助. (抱歉我笨)

> 1%*%1
     [,1]
[1,]    1
> 10%*%10
     [,1]
[1,]  100
> c(1:2)%*%c(1:2)
     [,1]
[1,]    5

Answer 1

这是一个矩阵乘法运算符!
来自 the documentation :

Description:

Multiplies two matrices, if they are conformable. If one argument is a vector, it will be promoted to either a row or column matrix to make the two arguments conformable. If both are vectors of the same length, it will return the inner product (as a matrix).

Usage:

x %*% y

Arguments:

x, y    numeric or complex matrices or vectors