Make an interaction variable and add to dataframe

Source: R/ff_interaction.R

Combine two factor variables to make an interaction variable. Factor level order is determined by the order in the variables themselves. Note, names of the factor variables should not be quoted. The name of the variable is created from the names of the two factors. The variable is also labelled with a name derived from any pre-existing labels.

ff_interaction(.data, ..., levels_sep = "_", var_sep = "_", label_sep = ":")

finalfit_interaction(
  .data,
  ...,
  levels_sep = "_",
  var_sep = "_",
  label_sep = ":"
)

Arguments

.data

Data frame.

...

The unquoted names of two factors.

levels_sep

Quoted character: how levels are separated in new variable.

var_sep

Quoted character: how variable name is separated.

label_sep

Quoted character: how variable label is separated

Value

Original data frame with new variable added via `dplyr::mutate`.

Examples


colon_s %>%
  ff_interaction(sex.factor, perfor.factor) %>%
    summary_factorlist("mort_5yr", "sex.factor_perfor.factor")
#> Note: dependent includes missing data. These are dropped.
#>            label     levels      Alive       Died
#>  Sex:Perforation  Female_No 238 (46.6) 186 (46.0)
#>                  Female_Yes    5 (1.0)    8 (2.0)
#>                     Male_No 259 (50.7) 205 (50.7)
#>                    Male_Yes    9 (1.8)    5 (1.2)