Apply Family

The apply family is a set of base R functions that apply another function to every element of a vector, list, or data structure, replacing many uses of explicit loops. lapply() always returns a list, sapply() tries to simplify the result into a vector or matrix, and vapply() works like sapply() but requires specifying the expected output type in advance. These functions predate the tidyverse's purrr package, which offers similar functionality with more consistent behavior.