The guess depends on the data, working through a list of likely candidates.
If the visit ID is known, it should be specified, ideally instead of calling
this function, but if unavoidable, using the visit_name parameter.
get_visit_name(x, visit_name = NULL)input data, typically a data frame
The name of the column in the data frame which contains the
patient or visit identifier. Typically this is the visit identifier, since
patients come leave and enter hospital with different ICD-9 codes. It is a
character vector of length one. If left empty, or NULL, then an
attempt is made to guess which field has the ID for the patient encounter
(not a patient ID, although this can of course be specified directly). The
guesses proceed until a single match is made. Data frames may be wide with
many matching fields, so to avoid false positives, anything but a single
match is rejected. If there are no successful guesses, and visit_id
was not specified, then the first column of the data frame is used.