Fast dcast for data.trame

dcast() transforms a data.trame from long to wide format, a little bit like tidyr::pivot_wider(). See data.table::dcast() for explanations.

dcast(
  data,
  formula,
  fun.aggregate = NULL,
  ...,
  margins = NULL,
  subset = NULL,
  fill = NULL,
  value.var = guess(data)
)

# S3 method for class 'data.trame'
dcast(
  data,
  formula,
  fun.aggregate = NULL,
  sep = "_",
  ...,
  margins = NULL,
  subset = NULL,
  fill = NULL,
  drop = TRUE,
  value.var = guess(data),
  verbose = getOption("datatable.verbose")
)

Arguments

data: A data.trame object.
formula: A formula LHS ~ RHS, see data.table::dcast() for details.
fun.aggregate: Te function to aggregate multiple data before dcasting.
...: Arguments passed to the aggregating function.
margins: Note implemented yet.
subset: Should the dcasting be done on a subset of the data?
fill: Value with which to fill missing cells.
value.var: The name of the column to use as value variable. If not provided it is "guessed" the guess() internal function is used to build a good default name.
sep: Character vector of length 1, used to separate parts of the variable names (_ by default).
drop: FALSE should dcast include all missing combinations?
verbose: Not used yet.

Value

A keyed data.trame is returned with the dcasted data.

Examples

# Adapted from first example of ?dcast.data.table
ChickWeight = as.data.trame(ChickWeight)
ChickWeight <- set_names(ChickWeight, tolower(names(ChickWeight)))
dtrm <- melt(ChickWeight, id.vars = 2:4)
dcast(dtrm, time ~ variable, fun.aggregate = mean)
#> # A data.trame: [12 × 2]
#> # Key:          time
#>     time weight
#>    <dbl>  <dbl>
#>  1     0   41.1
#>  2     2   49.2
#>  3     4   60.0
#>  4     6   74.3
#>  5     8   91.2
#>  6    10  108. 
#>  7    12  129. 
#>  8    14  144. 
#>  9    16  168. 
#> 10    18  190. 
#> 11    20  210. 
#> 12    21  219.

Arguments

Value

See also

Examples