The apply family in R

R's idiomatic replacement for explicit loops.

scores <- list(math = c(90, 85), art = c(70, 95, 80))

means <- sapply(scores, mean)
as_list <- lapply(scores, range)
counts <- vapply(scores, length, integer(1))

m <- matrix(1:6, nrow = 2)
row_sums <- apply(m, 1, sum)
col_max <- apply(m, 2, max)

pairs <- mapply(function(a, b) a * b, 1:3, 4:6)

How it works

1. sapply simplifies results; lapply keeps a list.
2. vapply fixes the return type for safety.
3. apply works over matrix rows or columns; mapply zips.

Keywords and builtins used here

• apply
• c
• function
• integer
• lapply
• list
• mapply
• matrix
• sapply
• vapply

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Step 1 of 5 in Vectorized thinking, step 10 of 20 in Language basics.

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