match {arules} | R Documentation

## Value Matching

### Description

Provides the generic function `match` and the S4 methods for associations and transactions. `match` returns a vector of the positions of (first) matches of its first argument in its second.

`%in%` is a more intuitive interface as a binary operator, which returns a logical vector indicating if there is a match or not for its left operand.

### Usage

    match(x,  table, nomatch = NA, incomparables = FALSE)

    x %in% table

### Arguments

`x` | an object of class `itemMatrix`, `transactions` or `associations`.
`table` | a set of associations or transactions to be matched against.
`nomatch` | the value to be returned in the case when no match is found.
`incomparables` | not implemented.

### Value

`match`: An integer vector of the same length as `x` giving the position in `table` of the first match if there is a match, otherwise `nomatch`.
`%in%`: A logical vector, indicating if a match was located for each element of `x`.

### See Also

`rules-class`, `itemsets-class`, `itemMatrix-class`

### Examples

    data("Adult")

    ## get unique transactions, count frequency of unique transactions
    ## and plot frequency of unique transactions
    vals <- unique(Adult)
    cnts <- tabulate(match(Adult, vals))
    plot(sort(cnts, decreasing=TRUE))

    ## find all transactions which are equal to transaction 10 in Adult
    which(Adult %in% Adult[10])

[Package arules version 0.6-3 Index]