1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
|
# compute the mean of the columns and the rows of a matrix
library(foreach)
# generate the input matrix
x <- matrix(rnorm(100 * 100), 100)
# compute the mean of each column of x
cmeans <- foreach(i=1:ncol(x), .combine=c) %do% mean(x[,i])
# check the results
expected <- colMeans(x)
print(all.equal(cmeans, expected))
# compute the mean of each row of x
rmeans <- foreach(i=1:nrow(x), .combine=c) %do% mean(x[i,])
# check the results
expected <- rowMeans(x)
print(all.equal(rmeans, expected))
|
