Convert frequency, case, or table form data into an array

Converts object (obj) in frequency, case or table form into an array. The column containing the frequencies (freq) must be supplied if obj is in frequency form.

Usage

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

Arguments

obj: Object to be converted to an array.
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 an array 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 array form

Details

Unclasses the as_table function to return an object in array form.

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

# Frequency form -> array form
as_array(freqForm, freq = "Freq") |> str()
#>  num [1:4, 1:4, 1:2] 32 53 10 3 11 50 10 30 10 25 ...
#>  - attr(*, "dimnames")=List of 3
#>   ..$ Hair: chr [1:4] "Black" "Brown" "Red" "Blond"
#>   ..$ Eye : chr [1:4] "Brown" "Blue" "Hazel" "Green"
#>   ..$ Sex : chr [1:2] "Male" "Female"
#>  - attr(*, "call")= language xtabs(formula = reformulate(cols, response = freq), data = obj)

# Warned if forgot to specify freq
as_array(freqForm) |> str()
#> Warning: Ensure a value for 'freq' was supplied if your data was in frequency form.
#>  int [1:4, 1:4, 1:2, 1:22] 0 0 0 0 0 0 0 0 0 0 ...
#>  - attr(*, "dimnames")=List of 4
#>   ..$ Hair: chr [1:4] "Black" "Brown" "Red" "Blond"
#>   ..$ Eye : chr [1:4] "Brown" "Blue" "Hazel" "Green"
#>   ..$ Sex : chr [1:2] "Male" "Female"
#>   ..$ Freq: chr [1:22] "2" "3" "4" "5" ...
#>  - attr(*, "call")= language xtabs(formula = reformulate(cols), data = obj)

# Case form -> array form
as_array(caseForm) |> str()
#>  int [1:4, 1:4, 1:2] 9 64 34 7 36 4 66 16 2 8 ...
#>  - attr(*, "dimnames")=List of 3
#>   ..$ Hair: chr [1:4] "Black" "Blond" "Brown" "Red"
#>   ..$ Eye : chr [1:4] "Blue" "Brown" "Green" "Hazel"
#>   ..$ Sex : chr [1:2] "Female" "Male"
#>  - attr(*, "call")= language xtabs(formula = reformulate(cols), data = obj)

# Frequency (tibble) form -> array form
as_array(tidy_freqForm, freq = "n") |> str()
#>  num [1:4, 1:4, 1:2] 9 64 34 7 36 4 66 16 2 8 ...
#>  - attr(*, "dimnames")=List of 3
#>   ..$ Hair: chr [1:4] "Black" "Blond" "Brown" "Red"
#>   ..$ Eye : chr [1:4] "Blue" "Brown" "Green" "Hazel"
#>   ..$ Sex : chr [1:2] "Female" "Male"
#>  - attr(*, "call")= language xtabs(formula = reformulate(cols, response = freq), data = obj)

# For specific dimensions
as_array(tidy_freqForm, freq = "n", dims = c("Hair", "Eye")) |> str()
#>  num [1:4, 1:4] 20 94 84 17 68 7 119 26 5 16 ...
#>  - attr(*, "dimnames")=List of 2
#>   ..$ Hair: chr [1:4] "Black" "Blond" "Brown" "Red"
#>   ..$ Eye : chr [1:4] "Blue" "Brown" "Green" "Hazel"
#>  - attr(*, "call")= language xtabs(formula = reformulate(cols, response = freq), data = obj)

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

as_array(freqForm, freq = "Freq", prop = TRUE) |> # proportions relative to grand total
  head(c(4,4,1)) 
#> , , Sex = Male
#> 
#>        Eye
#> Hair          Brown       Blue       Hazel       Green
#>   Black 0.054054054 0.01858108 0.016891892 0.005067568
#>   Brown 0.089527027 0.08445946 0.042229730 0.025337838
#>   Red   0.016891892 0.01689189 0.011824324 0.011824324
#>   Blond 0.005067568 0.05067568 0.008445946 0.013513514
#> 

# Marginalize proportions along "Sex" (i.e., male proportions sum to 1, female proportions sum to 1)
as_array(freqForm, freq = "Freq", prop = "Sex") |> head(c(4,4,1))
#> , , Sex = Male
#> 
#>        Eye
#> Hair         Brown       Blue      Hazel      Green
#>   Black 0.11469534 0.03942652 0.03584229 0.01075269
#>   Brown 0.18996416 0.17921147 0.08960573 0.05376344
#>   Red   0.03584229 0.03584229 0.02508961 0.02508961
#>   Blond 0.01075269 0.10752688 0.01792115 0.02867384
#> 

as_array(freqForm, freq = "Freq", prop = 3) |> head(c(4,4,1)) # Same as above
#> , , Sex = Male
#> 
#>        Eye
#> Hair         Brown       Blue      Hazel      Green
#>   Black 0.11469534 0.03942652 0.03584229 0.01075269
#>   Brown 0.18996416 0.17921147 0.08960573 0.05376344
#>   Red   0.03584229 0.03584229 0.02508961 0.02508961
#>   Blond 0.01075269 0.10752688 0.01792115 0.02867384
#> 

# Marginalize proportions along multiple variables
as_array(freqForm, freq = "Freq", prop = c("Hair", "Sex")) |> head(c(4,4,1))
#> , , Sex = Male
#> 
#>        Eye
#> Hair         Brown      Blue     Hazel      Green
#>   Black 0.57142857 0.1964286 0.1785714 0.05357143
#>   Brown 0.37062937 0.3496503 0.1748252 0.10489510
#>   Red   0.29411765 0.2941176 0.2058824 0.20588235
#>   Blond 0.06521739 0.6521739 0.1086957 0.17391304
#> 

as_array(freqForm, freq = "Freq", prop = c(1, 3)) |> head(c(4,4,1)) # Same as above
#> , , Sex = Male
#> 
#>        Eye
#> Hair         Brown      Blue     Hazel      Green
#>   Black 0.57142857 0.1964286 0.1785714 0.05357143
#>   Brown 0.37062937 0.3496503 0.1748252 0.10489510
#>   Red   0.29411765 0.2941176 0.2058824 0.20588235
#>   Blond 0.06521739 0.6521739 0.1086957 0.17391304
#> 

# Using dims and prop arguments in tandem
as_array(freqForm, freq = "Freq", dims = c("Hair", "Eye"), prop = TRUE)
#>        Eye
#> Hair         Brown       Blue      Hazel       Green
#>   Black 0.11486486 0.03378378 0.02533784 0.008445946
#>   Brown 0.20101351 0.14189189 0.09121622 0.048986486
#>   Red   0.04391892 0.02871622 0.02364865 0.023648649
#>   Blond 0.01182432 0.15878378 0.01689189 0.027027027
#> attr(,"call")
#> xtabs(formula = reformulate(cols, response = freq), data = obj)