Convert a data.frame (or tibble) into a multidimensional array

Usage

df_to_array(df, dim_var_names, value_var_name = "value")

Arguments

df: a data.frame() (or tibble::tibble()) in long format (each row contains one value for the intended array)
dim_var_names: a character() vector of variable names in df. All of these variables should be factors, or a warning will be produced.
value_var_name: a character() variable containing a variable name from df which contains the values for the intended array.

Value

an array() with dimensions defined by the variables in df listed in dim_var_names

Examples

library(dplyr)
library(tidyr)
#> 
#> Attaching package: ‘tidyr’
#> The following object is masked from ‘package:magrittr’:
#> 
#>     extract

df <- iris %>%
  tidyr::pivot_longer(
    names_to = "parameter",
    cols = c("Sepal.Length", "Sepal.Width", "Petal.Width", "Petal.Length")
  ) %>%
  mutate(parameter = factor(parameter, levels = unique(parameter)))
arr <- df %>%
  serocalculator:::df_to_array(
     dim_var_names = c("parameter", "Species"))
ftable(arr[,,1:5])
#>                         obs   1   2   3   4   5
#> parameter    Species                           
#> Sepal.Length setosa         5.1 4.9 4.7 4.6 5.0
#>              versicolor     7.0 6.4 6.9 5.5 6.5
#>              virginica      6.3 5.8 7.1 6.3 6.5
#> Sepal.Width  setosa         3.5 3.0 3.2 3.1 3.6
#>              versicolor     3.2 3.2 3.1 2.3 2.8
#>              virginica      3.3 2.7 3.0 2.9 3.0
#> Petal.Width  setosa         0.2 0.2 0.2 0.2 0.2
#>              versicolor     1.4 1.5 1.5 1.3 1.5
#>              virginica      2.5 1.9 2.1 1.8 2.2
#> Petal.Length setosa         1.4 1.4 1.3 1.5 1.4
#>              versicolor     4.7 4.5 4.9 4.0 4.6
#>              virginica      6.0 5.1 5.9 5.6 5.8