Split a data frame by variables.
Split a data frame into pieces based on variable contained in that data frame
splitter_d(data, .variables = NULL, drop = TRUE)
data |
data frame |
.variables |
a quoted list of variables |
drop |
drop unnused factor levels? |
This is the workhorse of the d*ply functions. Based on the variables
you supply, it breaks up a single data frame into a list of data frames,
each containing a single combination from the levels of the specified
variables.
This is basically a thin wrapper around split which
evaluates the variables in the context of the data, and includes enough
information to reconstruct the labelling of the data frame after
other operations.
a list of data.frames, with attributes that record split details
Other splitter functions:
splitter_a()
plyr:::splitter_d(mtcars, .(cyl)) plyr:::splitter_d(mtcars, .(vs, am)) plyr:::splitter_d(mtcars, .(am, vs)) mtcars$cyl2 <- factor(mtcars$cyl, levels = c(2, 4, 6, 8, 10)) plyr:::splitter_d(mtcars, .(cyl2), drop = TRUE) plyr:::splitter_d(mtcars, .(cyl2), drop = FALSE) mtcars$cyl3 <- ifelse(mtcars$vs == 1, NA, mtcars$cyl) plyr:::splitter_d(mtcars, .(cyl3)) plyr:::splitter_d(mtcars, .(cyl3, vs)) plyr:::splitter_d(mtcars, .(cyl3, vs), drop = FALSE)
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