Uses the string from the select_choices_or_calculations
for the meta data to create a matrix of codes and their mapped
labels.
fieldChoiceMapping(object, field_name, ...)# S3 method for character
fieldChoiceMapping(object, field_name, ...)
# S3 method for redcapApiConnection
fieldChoiceMapping(object, field_name, ...)
Returns a matrix with two columns, choice_value and choice_label
redcapConnection or character(1). When character, is
matches the format of the meta data field choices
(i.e. rcon$meta_data()$select_choices_or_calculations).
character(1) gives the field name for which to
make the choice mapping.
Arguments to pass to other methods