convert function

Pre-process data for Midas imputation

convert pre-processes datasets to enable user-friendly interface with the main train() function.

convert(data, bin_cols = NULL, cat_cols = NULL, minmax_scale = FALSE)

Arguments

• data: Either an object of class data.frame, data.table, or a path to a regular, delimited file
• bin_cols, cat_cols: A vector, column names corresponding to binary and categorical variables respectively
• minmax_scale: Boolean, indicating whether to scale all numeric columns between 0 and 1, to improve model convergence

Returns

Returns custom S3 object of class `midas_preproc' containing:

• data -- processed version of input data,
• bin_list -- vector of binary variable names
• cat_lists -- embedded list of one-hot encoded categorical variable names
• minmax_params -- list of min. and max. values for each numeric object scaled

List containing converted data, categorical and binary labels to be imported into the imputation model, and scaling parameters for post-imputation transformations.

Details

The function has two advantages over manual pre-processing:

1. Utilises data.table for fast read-in and processing of large datasets
2. Outputs an object that can be passed directly to train() without re-specifying column names etc.

For more information, see Lall and Robinson (2023): doi:10.18637/jss.v107.i09.

Examples

data = data.frame(a = sample(c("red","yellow","blue",NA),100, replace = TRUE),
                  b = 1:100,
                  c = sample(c("YES","NO",NA),100,replace = TRUE),
                  d = runif(100),
                  e = sample(c("YES","NO"), 100, replace = TRUE),
                  f = sample(c("male","female","trans","other",NA), 100, replace = TRUE),
                  stringsAsFactors = FALSE)

bin <- c("c","e")
cat <- c("a","f")

convert(data, bin_cols = bin, cat_cols = cat)

References

Rdpack::insert_ref(key="rmidas_jss",package="rMIDAS")