Add the missing combinations of x and y

Source: R/asymmetrise.R

Adds rows to the input data table to include any combinations of .x and .y that are not already present. All other columns (if any) are set to NA

bind_missing_combs(df, .x, .y)

Arguments

df

input data table
.x, .y

names of the columns for which to add missing comparisons

Value

a data table with the new rows

Examples

df <- data.frame(
  a = c("A", "B"),
  b = c("C", "A"),
  untouched = c(1, 2),
  stringsAsFactors = FALSE
)
df

#>   a b untouched
#> 1 A C         1
#> 2 B A         2

bind_missing_combs(df, a, b)

#>   a b untouched
#> 1 A C         1
#> 2 B A         2
#> 3 A A        NA
#> 4 C A        NA
#> 5 A B        NA
#> 6 B B        NA
#> 7 C B        NA
#> 8 B C        NA
#> 9 C C        NA