PlackettLuce: aggregate – R documentation

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aggregate

Aggregate Rankings

Description

Aggregate rankings, returning an "aggregated_rankings" object of the unique rankings and their frequencies. The frequencies can be extracted via the function freq().

Usage

## S3 method for class 'rankings'
aggregate(x, freq = NULL, ...)

as.aggregated_rankings(x, ...)

## S3 method for class 'aggregated_rankings'
x[i, j, ..., drop = FALSE, as.aggregated_rankings = TRUE]

freq(x)

Arguments

`x`	A `"rankings"` object for `aggregate()`; an object that can be coerced to a `"aggregated_rankings"` object for `as.aggregated_rankings()`, otherwise an `"aggregated_rankings"` object.
`freq`	A vector of frequencies for rankings that have been previously aggregated.
`...`	Additional arguments, currently unused.
`i`	indices specifying rankings to extract, as for `[`.
`j`	indices specifying items to extract, as for `[`.
`drop`	if `TRUE` return single row/column matrices as a vector.
`as.aggregated_rankings`	if `TRUE` create an `"aggregated_rankings"` object from the indexed rankings. Otherwise index the underlying matrix of ranks and return in a data frame with the corresponding frequencies.

Value

A data frame of class "aggregated_rankings", with columns

`ranking`	A `"rankings"` object of the unique rankings.
`freq`	The corresponding frequencies.

Methods are available for rbind() and as.matrix().

Examples

# create a rankings object with duplicated rankings
R <- matrix(c(1, 2, 0, 0,
              0, 1, 2, 3,
              2, 1, 1, 0,
              1, 2, 0, 0,
              2, 1, 1, 0,
              1, 0, 3, 2), nrow = 6, byrow = TRUE)
colnames(R) <- c("apple", "banana", "orange", "pear")
R <- as.rankings(R)

# aggregate the rankings
A <- aggregate(R)

# subsetting applies to the rankings, e.g. first two unique rankings
A[1:2]

# (partial) rankings of items 2 to 4 only
A[, 2:4]

# convert to a matrix
as.matrix(A)

# frequencies are automatically used as weights by PlackettLuce()
mod <- PlackettLuce(A)
mod$weights

PlackettLuce

Plackett-Luce Models for Rankings

v0.4.0

GPL-3

Authors

Heather Turner [aut, cre] (<https://orcid.org/0000-0002-1256-3375>), Ioannis Kosmidis [aut] (<https://orcid.org/0000-0003-1556-0302>), David Firth [aut] (<https://orcid.org/0000-0003-0302-2312>), Jacob van Etten [ctb] (<https://orcid.org/0000-0001-7554-2558>)

Initial release