Convert frequency, case, or table form data into a matrix.

Converts object (obj) in frequency, case or table form into a matrix of specified dimensions (dims). The column containing the frequencies (freq) must be supplied if obj is in frequency form.

Usage

as_matrix(obj, freq = NULL, dims = NULL, prop = NULL)

Arguments

obj: Object to be converted into a matrix.
freq: If obj is in frequency form, this is the name of the frequency column. Leave as NULL if obj is in any other form.
dims: A character vector of dimensions. If not specified, all variables apart from freq will be used as dimensions.
prop: If set to TRUE, returns a matrix of proportions (that sum to 1). May also be set to a character or numeric vector of dimensions to be used as margins from which proportions will be computed.

Value

Object in matrix form.

Details

First converts obj into an array using as_array. Then a check is made to ensure the user inputted a 2D obj. If obj is not 2D, an error is returned. If obj is 2D, as.matrix is applied.

Author

Gavin M. Klorfine

Examples

library(vcdExtra)

data("HairEyeColor")

freqForm <- as.data.frame(HairEyeColor) # Generate frequency form data
tidy_freqForm <- dplyr::as_tibble(HairEyeColor) # Generate tidy frequency form data
caseForm <- expand.dft(freqForm) # Generate case form data
arrayDat <- as_array(HairEyeColor) # Generate an array

# Table form -> matrix
as_matrix(HairEyeColor, dims = c("Hair", "Sex")) |> str()
#>  num [1:4, 1:2] 56 143 34 46 52 143 37 81
#>  - attr(*, "dimnames")=List of 2
#>   ..$ Hair: chr [1:4] "Black" "Brown" "Red" "Blond"
#>   ..$ Sex : chr [1:2] "Male" "Female"

# Frequency form -> matrix
as_matrix(freqForm, freq = "Freq", dims = c("Hair", "Sex")) |> str()
#>  num [1:4, 1:2] 56 143 34 46 52 143 37 81
#>  - attr(*, "dimnames")=List of 2
#>   ..$ Hair: chr [1:4] "Black" "Brown" "Red" "Blond"
#>   ..$ Sex : chr [1:2] "Male" "Female"
#>  - attr(*, "call")= language xtabs(formula = reformulate(cols, response = freq), data = obj)

# Case form -> matrix form
as_matrix(caseForm, dims = c("Hair", "Sex")) |> str()
#>  int [1:4, 1:2] 52 81 143 37 56 46 143 34
#>  - attr(*, "dimnames")=List of 2
#>   ..$ Hair: chr [1:4] "Black" "Blond" "Brown" "Red"
#>   ..$ Sex : chr [1:2] "Female" "Male"
#>  - attr(*, "call")= language xtabs(formula = reformulate(cols), data = obj)

# Frequency (tibble) form -> matrix form
as_matrix(tidy_freqForm, freq = "n", dims = c("Hair", "Sex")) |> str()
#>  num [1:4, 1:2] 52 81 143 37 56 46 143 34
#>  - attr(*, "dimnames")=List of 2
#>   ..$ Hair: chr [1:4] "Black" "Blond" "Brown" "Red"
#>   ..$ Sex : chr [1:2] "Female" "Male"
#>  - attr(*, "call")= language xtabs(formula = reformulate(cols, response = freq), data = obj)

#-----For proportions-----#

# Proportions relative to grand total
as_matrix(HairEyeColor, dims = c("Hair", "Sex"), prop = TRUE)
#>        Sex
#> Hair          Male     Female
#>   Black 0.09459459 0.08783784
#>   Brown 0.24155405 0.24155405
#>   Red   0.05743243 0.06250000
#>   Blond 0.07770270 0.13682432

# Marginalize proportions along "Sex" (i.e., male proportions sum to 1, 
# female proportions sum to 1)
as_matrix(HairEyeColor, dims = c("Hair", "Sex"), prop = "Sex")
#>        Sex
#> Hair         Male    Female
#>   Black 0.2007168 0.1661342
#>   Brown 0.5125448 0.4568690
#>   Red   0.1218638 0.1182109
#>   Blond 0.1648746 0.2587859

as_matrix(HairEyeColor, dims = c("Hair", "Sex"), prop = 2) # Same as above
#>        Sex
#> Hair         Male    Female
#>   Black 0.2007168 0.1661342
#>   Brown 0.5125448 0.4568690
#>   Red   0.1218638 0.1182109
#>   Blond 0.1648746 0.2587859