plyr (version 1.6)

llply: Split list, apply function, and return results in a list.

Description

For each element of a list, apply function, keeping results as a list. llply is equivalent to lapply except that it will preserve labels and can display a progress bar.

Usage

llply(.data, .fun = NULL, ..., .progress = "none",
  .inform = FALSE, .parallel = FALSE)

Arguments

.fun

function to apply to each piece

...

other arguments passed on to .fun

.progress

name of the progress bar to use, see create_progress_bar

.data

list to be processed

.parallel

if TRUE, apply function in parallel, using parallel backend provided by foreach

.inform

produce informative error messages? This is turned off by by default because it substantially slows processing speed, but is very useful for debugging

Value

• list of results

Input

This function splits lists by elements and combines the result into a data frame.

Output

If there are no results, then this function will return a list of length 0 (list()).

References

Hadley Wickham (2011). The Split-Apply-Combine Strategy for Data Analysis. Journal of Statistical Software, 40(1), 1-29. http://www.jstatsoft.org/v40/i01/.

See Also

Other list input: laply, ldply

Other list output: alply, dlply

Examples

llply(llply(mtcars, round), table)
llply(baseball, summary)
# Examples from ?lapply
x <- list(a = 1:10, beta = exp(-3:3), logic = c(TRUE,FALSE,FALSE,TRUE))

llply(x, mean)
llply(x, quantile, probs = 1:3/4)