as_rvar_factor {posterior}

Coerce to a factor random variable

Description

Convert x to an rvar_factor or rvar_ordered object.

Usage

as_rvar_factor(x, dim = NULL, dimnames = NULL, nchains = NULL, ...)

as_rvar_ordered(x, dim = NULL, dimnames = NULL, nchains = NULL, ...)

Arguments

x

(multiple options) An object that can be converted to an rvar, such as a vector, array, or an rvar itself.

dim

(integer vector) One or more integers giving the maximal indices in each dimension to override the dimensions of the rvar to be created (see dim()). If NULL (the default), dim is determined by the input. NOTE: This argument controls the dimensions of the rvar, not the underlying array, so you cannot change the number of draws using this argument.

dimnames

(list) Character vectors giving the names in each dimension to override the names of the dimensions of the rvar to be created (see dimnames()). If NULL (the default), this is determined by the input. NOTE: This argument controls the names of the dimensions of the rvar, not the underlying array.

nchains

(positive integer) The number of chains. The default is 1.

...

Arguments passed on to base::factor

levels

an optional vector of the unique values (as character strings) that x might have taken. The default is the unique set of values taken by as.character(x), sorted into increasing order of x. Note that this set can be specified as smaller than sort(unique(x)).

labels

either an optional character vector of labels for the levels (in the same order as levels after removing those in exclude), or a character string of length 1. Duplicated values in labels can be used to map different values of x to the same factor level.

exclude

a vector of values to be excluded when forming the set of levels. This may be factor with the same level set as x or should be a character.

ordered

logical flag to determine if the levels should be regarded as ordered (in the order given).

nmax

an upper bound on the number of levels; see ‘Details’.

Details

For objects that are already rvars, returns them (with modified dimensions if dim is not NULL), possibly adding levels using the unique values of the draws of the rvar (if the object is not already factor-like).

For numeric, logical, factor, or character vectors or arrays, returns an rvar_factor or rvar_ordered with a single draw and the same dimensions as x. This is in contrast to the rvar_factor() and rvar_ordered() constructors, which treats the first dimension of x as the draws dimension. As a result, as_rvar_factor() and as_rvar_ordered() are useful for creating constants.

Value

An object of class "rvar_factor" or "rvar_ordered" representing a random variable.

See Also

rvar(), rvar_factor(), and rvar_ordered() to construct rvars directly. See rdo(), rfun(), and rvar_rng() for higher-level interfaces for creating rvars.

Examples

# You can use as_rvar_factor() to create "constant" rvars (having only one draw):
x <- as_rvar_factor("a")
x

# Such constants can be of arbitrary shape:
as_rvar_factor(letters[1:4])
as_rvar_ordered(matrix(letters[1:10], nrow = 5))
as_rvar_factor(array(letters[1:12], dim = c(2, 3, 2)))