plyr (version 1.6)

laply: Split list, apply function, and return results in an array.

Description

For each element of a list, apply function then combine results into an array. laply is similar in spirit to sapply except that it will always return an array, and the output is transposed with respect sapply - each element of the list corresponds to a column, not a row.

Usage

laply(.data, .fun = NULL, ..., .progress = "none", .drop
  = TRUE, .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

.drop

should extra dimensions of length 1 in the output be dropped, simplifying the output. Defaults to TRUE

Value

• if results are atomic with same type and dimensionality, a vector, matrix or array; otherwise, a list-array (a list with dimensions)

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 vector of length 0 (vector()).

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 array output: aaply, daply

Other list input: ldply, llply

Examples

laply(baseball, is.factor)
# cf
ldply(baseball, is.factor)
colwise(is.factor)(baseball)

laply(seq_len(10), identity)
laply(seq_len(10), rep, times = 4)
laply(seq_len(10), matrix, nrow = 2, ncol = 2)