Add Start End Events

Prepend a path_start and append a path_end synthetic event to each path.

Idempotent: a path that already starts or ends with these events is left unchanged on that side.

You normally don't need to call this directly — transition_graph, step_matrix, and step_sankey insert path_start/path_end themselves, each using its own path_col. Calling this upfront bakes in one specific path definition and can produce misleading boundaries if a widget is later given a different path_col.

Usage

stream.add_start_end_events()

How it works

path_start and path_end are the boundary markers that make "where do paths begin?" and "where do users leave?" answerable as ordinary event questions — a Step Matrix anchored at path_end, or a cart → path_end edge on the Transition Graph that reads as "abandoned here".

Before:

• u1: home → cart
• u2: home

stream.add_start_end_events()

After — each marker copies the timestamp of the event it brackets, so a single-event path gets both at the same moment:

You rarely need to call this yourself: transition_graph, step_matrix and step_sankey add the markers on the fly, each using its own path_col. Calling it upfront freezes one definition of a path into the data, which then quietly mislabels the boundaries if a widget is later given a different path_col — for example after split_sessions, where per-user markers would sit in the middle of most sessions.

Parameters