Sequence input shared by the sequence verbs

Sequence input

Every verb that reads sequences reads them the same way:

Long event table: a data.frame with one event per row. action names the state column, actor the column (or columns) that identify whose events they are, session the column (or columns) that split an actor's events into sessions, and time the column that orders them: timestamps in any common date-time format, Unix times, or positions; row order when NULL. A column named action, time, session or session_id (in any case) is used when its argument is NULL; session = FALSE switches the session detection off. When time is given, a gap of more than time_threshold seconds between consecutive events starts a new sequence (default 900, fifteen minutes); time_threshold = FALSE keeps each actor or session in one sequence however long the gaps. timezone is the time zone of timestamps that carry none (default "UTC"). Events with a missing actor or session raise hypergraphs_bad_input; a missing action stays in its sequence as a gap. Without actor all events form one sequence, announced by the message hypergraphs_single_sequence.
Wide data.frame or character matrix: one sequence per row; trailing NAs end a sequence.
List: one character vector per sequence.
Model object: a netobject, netobject_group, tna or cograph_network that carries its sequence data.

These are the conventions of the tna family of packages, and the same call builds the same sequences there.

A missing state anywhere but at the end of a wide row is a gap. The memory verbs (hon(), mogen(), hypa(), markov_order(), memory(), hg_bootstrap(), hg_compare()) split a sequence at every gap into its runs of observed states: no transition is counted across or into a gap and no state "NA" is created (a state spelled "NA" is an ordinary state). hg_bootstrap() and hg_compare() still resample the original sequences, each with all its runs. Repeats are collapsed within a run. State labels containing " -> " (the notation of memory nodes) are refused with hypergraphs_bad_input by the verbs whose results name paths.

A data.frame with columns named like an event table (code, state, user, timestamp, ...) that is passed without action = and has no action column raises hypergraphs_long_format (a hypergraphs_bad_input): read as wide, its actor ids and times would silently become states. actor, time or session without an action column raises hypergraphs_bad_input.