lapply {base} | R Documentation |

## Apply a Function over a List or Vector

### Description

`lapply`

returns a list of the same length as `X`

. Each
element of which is the result of applying `FUN`

to the
corresponding element of `X`

.

`sapply`

is a “user-friendly” version of `lapply`

also accepting vectors as `X`

, and returning a vector or matrix
with `dimnames`

if appropriate.

`replicate`

is a wrapper for the common use of `sapply`

for
repeated evaluation of an expression (which will usually involve
random number generation).

### Usage

lapply(X, FUN, ...)
sapply(X, FUN, ..., simplify = TRUE, USE.NAMES = TRUE)
replicate(n, expr, simplify = TRUE)

### Arguments

`X` |
list or vector to be used. |

`FUN` |
the function to be applied.
In the case of functions like `+` ,
`%*%` , etc., the function name must be quoted. |

`...` |
optional arguments to `FUN` . |

`simplify` |
logical; should the result be simplified to a vector
or matrix if possible? |

`USE.NAMES` |
logical; if `TRUE` and if `X` is character,
use `X` as `names` for the result unless it had names
already. |

`n` |
Number of replications. |

`expr` |
Expression to evaluate repeatedly. |

### References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988)
*The New S Language*.
Wadsworth & Brooks/Cole.

### See Also

`apply`

, `tapply`

.

### Examples

x <- list(a = 1:10, beta = exp(-3:3), logic = c(TRUE,FALSE,FALSE,TRUE))
# compute the list mean for each list element
lapply(x,mean)
# median and quartiles for each list element
lapply(x, quantile, probs = 1:3/4)
sapply(x, quantile)
i39 <- sapply(3:9, seq) # list of vectors
sapply(i39, fivenum)
hist(replicate(100, mean(rexp(10))))

[Package

*base* version 2.1.0

Index]