Get paired entities from a data frame based on the other column

Usage

paired(df = ".", id, compare, idents = 2, uniq = TRUE)

Arguments

df: The data frame.
id: The column name in df for the ids to be returned in the final output
compare: The column name in df to compare the values for each id in id.
idents: The values in compare to compare. It could be either an an integer or a vector. If it is an integer, the number of values in compare must be the same as the integer for the id to be regarded as paired. If it is a vector, the values in compare must be the same as the values in idents for the id to be regarded as paired.
uniq: Whether to return unique ids or not. Default is TRUE. If FALSE, you can mutate the meta data frame with the returned ids. Non-paired ids will be NA.

Value

A vector of paired ids (in id column)

Examples

df <- data.frame(
    id = c("A", "A", "B", "B", "C", "C", "D", "D"),
    compare = c(1, 2, 1, 1, 1, 2, 1, 2)
)
paired(df, id, compare, 2)
#> [1] "A" "B" "C" "D"
paired(df, id, compare, c(1, 2))
#> [1] "A" "C" "D"
paired(df, id, compare, c(1, 2), uniq = FALSE)
#> [1] "A" "A" NA  NA  "C" "C" "D" "D"