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alstat/explanation-of-apply.R

Last active March 20, 2019 13:56
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explanation-of-apply.R
set.seed(1)
x1 <- rnorm(10)
x2 <- rnorm(10)
out <- cbind(x1, x2)
colMeans(out)
# colMeans can be computed as follows as well
apply(out, 2, mean)
# apply - applies a mean function to column (indicated by 2) of out matrix
# for sd change mean to sd
apply(out, 2, sd)
# this is equivalent to
c(sd(out[, 1]), sd(out[, 2]))
# for median
apply(out, 2, median)
# this is equivalent to
c(median(out[, 1]), median(out[, 2]))
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