ldply {plyr}R Documentation

Split list, apply function, and return results in a data frame

Description

For each element of a list, apply function then combine results into a data frame

Usage

ldply(.data, .fun = NULL, ..., .progress = "none")

Arguments

.data list to be processed
.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

Details

All plyr functions use the same split-apply-combine strategy: they split the input into simpler pieces, apply .fun to each piece, and then combine the pieces into a single data structure. This function splits lists by elements and combines the result into a data frame. If there are no results, then this function will return a data frame with zero rows and columns (data.frame()).

The most unambiguous behaviour is achieved when .fun returns a data frame - in that case pieces will be combined with rbind.fill. If .fun returns an atomic vector of fixed length, it will be rbinded together and converted to a data frame. Any other values will result in an error.

Value

a data frame

Author(s)

Hadley Wickham <h.wickham@gmail.com>


[Package plyr version 0.1.5 Index]