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 array with dimnames if appropriate.

Usage

lapply(X, FUN, ...)
sapply(X, FUN, ..., simplify = TRUE, USE.NAMES = 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 if possible?
USE.NAMES	logical; if TRUE and if X is character, use X as names for the result unless it had names already.

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)
str(i39 <- sapply(3:9, seq))# list of vectors
sapply(i39, fivenum)

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