mapply: Apply a Function to Multiple List or Vector Arguments

Description

mapply is a multivariate version of sapply. mapply applies FUN to the first elements of each ... argument, the second elements, the third elements, and so on. Arguments are recycled if necessary.

Usage

mapply(FUN, ..., MoreArgs = NULL, SIMPLIFY = TRUE, USE.NAMES = TRUE)

Arguments

FUN

function to apply, found via match.fun.

...

arguments to vectorize over (vectors or lists of strictly positive length, or all of zero length). See also ‘Details’.

MoreArgs

a list of other arguments to FUN.

SIMPLIFY

logical or character string; attempt to reduce the result to a vector, matrix or higher dimensional array; see the simplify argument of sapply.

USE.NAMES

logical; use names if the first ... argument has names, or if it is a character vector, use that character vector as the names.

Value

A list, or for SIMPLIFY = TRUE, a vector, array or list.

Details

mapply calls FUN for the values of ... (re-cycled to the length of the longest, unless any have length zero), followed by the arguments given in MoreArgs. The arguments in the call will be named if ... or MoreArgs are named.

Arguments with classes in ... will be accepted, and their subsetting and length methods will be used.

Examples

Run this code

mapply(rep, 1:4, 4:1)

mapply(rep, times = 1:4, x = 4:1)

mapply(rep, times = 1:4, MoreArgs = list(x = 42))

mapply(function(x, y) seq_len(x) + y,
       c(a =  1, b = 2, c = 3),  # names from first
       c(A = 10, B = 0, C = -10))

word <- function(C, k) paste(rep.int(C, k), collapse = "")
utils::str(mapply(word, LETTERS[1:6], 6:1, SIMPLIFY = FALSE))

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