R: Apply a Function to Multiple List or Vector Arguments

mapply {base} | R Documentation

## 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).
`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.

### 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.

### Value

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

### See Also

`sapply`, after which `mapply()` is modelled.

`outer`, which applies a vectorized function to all combinations of two arguments.

### Examples

    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))

[Package base version 2.15.1 Index]