如何创建由给定矢量集的所有组合（总和）组成的矩阵？

Question

假设我有三个（行）向量：

c1*x1 + c2*x2 + c3*x3

我想要c(i)所有可能的总和{{1}}，其中{{1}}为零或一。显然有八种这样的组合。我希望在更大规模的R中做到这一点（有8个向量，所以256行矩阵），但我是一个编码业余爱好者并且正在努力。

Answer 1

#these vector should be combined in one data structure when you create them
x1 = c(0, 1, 0, 1, 0)    
x2 = c(1, 2, 3, 4, 5)    
x3 = c(2, 3, 4, 5, 6)

#create a matrix
m <- cbind(x1, x2, x3)

#all combinations of coefficients
coef <- t(do.call(expand.grid, rep(list(c(0, 1)), 3)))
#     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8]
#Var1    0    1    0    1    0    1    0    1
#Var2    0    0    1    1    0    0    1    1
#Var3    0    0    0    0    1    1    1    1

#matrix product
m %*% coef
#     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8]
#[1,]    0    0    1    1    2    2    3    3
#[2,]    0    1    2    3    3    4    5    6
#[3,]    0    0    3    3    4    4    7    7
#[4,]    0    1    4    5    5    6    9   10
#[5,]    0    0    5    5    6    6   11   11