alply {plyr} | R Documentation |
For each slice of an array, apply function then combine results into a list.
alply(.data, .margins, .fun = NULL, ..., .expand = TRUE, .progress = "none", .inform = FALSE, .parallel = FALSE, .paropts = NULL, .dims = FALSE)
.fun |
function to apply to each piece |
... |
other arguments passed on to |
.progress |
name of the progress bar to use, see
|
.parallel |
if |
.paropts |
a list of additional options passed into
the |
.inform |
produce informative error messages? This is turned off by by default because it substantially slows processing speed, but is very useful for debugging |
.data |
matrix, array or data frame to be processed |
.margins |
a vector giving the subscripts to split
up |
.expand |
if |
.dims |
if |
The list will have "dims" and "dimnames" corresponding to
the margins given. For instance alply(x, c(3,2),
...)
where x
has dims c(4,3,2)
will give a
result with dims c(2,3)
.
alply
is somewhat similar to apply
for cases where the results are not atomic.
list of results
This function splits matrices, arrays and data frames by dimensions
If there are no results, then this function will return a
list of length 0 (list()
).
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/.
Other array input: a_ply
,
aaply
, adply
Other list output: dlply
,
llply
, mlply
alply(ozone, 3, quantile) alply(ozone, 3, function(x) table(round(x)))