Create item tuples.

If item inclusions or exclusions are stored as a character vector, itemTuples separates this vector and creates item pairs ('tuples').

Usage

itemTuples(items, idCol = "ID", infoCol, sepPattern = ", ")

Arguments

items

A data.frame with information on an item pool.

idCol

character or integer indicating the item ID column in items.

infoCol

character or integer indicating the column in items which contains information on the tuples.

sepPattern

String which should be used for separating item IDs in the infoCol column.

Value

A data.frame with two columns.

Details

Tuples can be used by itemExclusionConstraint to set up exclusion constraints and by itemInclusionConstraint to set up inclusion constraints. Note that a separator pattern has to be used consistently throughout the column (e.g. ", ").

Examples

# Example data.frame
items <- data.frame(ID = c("item1", "item2", "item3", "item4"),
                     exclusions = c("item2, item3", NA, NA, NA))

# Create tuples
itemTuples(items = items, idCol = "ID", infoCol = 2,
                    sepPattern = ", ")
#>      [,1]    [,2]   
#> [1,] "item1" "item2"
#> [2,] "item1" "item3"