Section 8 Function apply: Special Case

8.1 Special case

rowSums = apply(x, 1, sum)

rowMeans = apply(x, 1, mean)

colSums = apply(x, 2, sum)

colMeans = apply(x, 2, mean)

8.2 Preserve rows or columns

x <- c(1:15)
y <- matrix(data=x, nrow=5, ncol=3)
y
z <- y
z[2,3] <- NA
z

apply(X = z, MARGIN = 1, FUN = sum, na.rm = TRUE)
rowSums(x = z, na.rm = TRUE)

apply(X = z, MARGIN = 1, FUN = mean, na.rm = TRUE)
rowMeans(x = z, na.rm = TRUE)

apply(X = z, MARGIN = 2, FUN = sum, na.rm = TRUE)
colSums(x = z, na.rm = TRUE)

apply(X = z, MARGIN = 2, FUN = mean, na.rm = TRUE)
colMeans(x = z, na.rm = TRUE)