Transform a data frame to a numeric matrix by one-hot encoding factors. The last factor value is always omitted to prevent having a singular matrix when adding a column of 1s (intercept) in models.
covar_from_df(df)A data frame.
A numeric matrix.
mat <- covar_from_df(iris)
head(mat)
#> Sepal.Length Sepal.Width Petal.Length Petal.Width Speciesversicolor
#> 1 5.1 3.5 1.4 0.2 0
#> 2 4.9 3.0 1.4 0.2 0
#> 3 4.7 3.2 1.3 0.2 0
#> 4 4.6 3.1 1.5 0.2 0
#> 5 5.0 3.6 1.4 0.2 0
#> 6 5.4 3.9 1.7 0.4 0
#> Speciesvirginica
#> 1 0
#> 2 0
#> 3 0
#> 4 0
#> 5 0
#> 6 0