Given a data frame, this function turns non-numeric columns into factors.
factorizeNonNumericColumns(data)
The input data frame with non-numeric columns turned into factors.
A data frame. Non-data frame inputs (e.g., a matrix) are coerced to a data frame.
Peter Langfelder
A column is considered numeric if its storage mode is numeric or if it is a character vector, it only contains character representations of numbers and possibly missing values encoded as "NA", "NULL", "NO DATA".