cast_simple {popEpi} | R Documentation |
Cast data.table
/data.frame
from long format to wide format
Description
Convenience function for using dcast.data.table
;
inputs are character strings (names of variables) instead of a formula.
Usage
cast_simple(data = NULL, columns = NULL, rows = NULL, values = NULL)
Arguments
data |
a |
columns |
a character string vector; the (unique combinations of the) levels of these variable will be different rows |
rows |
a character string vector; the (unique combinations of the) levels of these variable will be different columns |
values |
a character string; the variable which will be represented
on rows and columns as specified by |
Details
This function is just a small interface for dcast
/
dcast.data.table
and less flexible than the originals.
Note that all data.table
objects are also data.frame
objects, but that each have their own dcast
method.
dcast.data.table
is faster.
If any values in value.vars
need to be
aggregated, they are aggregated using sum
.
See ?dcast
.
Value
A 'data.table' just like '[data.table::dcast]'.
Author(s)
Matti Rantanen, Joonas Miettinen
Examples
library("data.table")
## e.g. silly counts from a long-format table to a wide format
test <- data.table::copy(popEpi::sire)
test$dg_y <- year(test$dg_date)
test$ex_y <- year(test$ex_date)
tab <- ltable(test, c("dg_y","ex_y"))
cast_simple(tab, columns='dg_y', rows="ex_y", values="obs")