Treat all metadata with more than two values as numeric, unless they are in the vector with categoric values. Metadata with two values (without counting missing values) are treated as binary (so categoric). Metadata are supposed to have been filtered previously (so constant rows were removed). Note that a message is printed to indicate which metadata type was assigned and to warn about numeric metadata with non-numeric values.
assignMetadataTypes(data, categoric = c())
a metadata matrix with rows as samples and columns as items or a dataframe with metadata items as columns
metadata items to be treated as categoric data