`vp.features.sessions`

Gap-based sessions per user (catalog/sessions.viv).

Part of the distribution vipyr; it runs from a checkout of the repository. Planned on PyPI as pip install vipyr.

Signature

vp.features.sessions(df=None, n=500, gap='30min')

Parameters

df : pandas.DataFrame, default None: The event table, rows in any order; None makes a synthetic one of n rows.
n : int, default 500: Rows of the synthetic table when df is None. Range: >= 1.
gap : str, default '30min'

Returns

A frozen SessionsResult. Iterating it gives the fields below in order; it also has params, tests, log and check().

frame : pandas.DataFrame: The features, one row per input row, in the input's order and index: session_start, session_index, secs_since_start, n_prev_in_session.

column of frame	definition
`session_start`	time of the session's first event; with `user`, the session's id
`session_index`	number of the user's sessions that started before this one
`secs_since_start`	`(ts - session_start)` in seconds
`n_prev_in_session`	events of the session with a time before `ts` (same instant excluded)

Raises

TypeError: An argument of the wrong type, or an unknown keyword.
vipyr.VivBuildError: An ImportError: no C compiler, or the program's C does not build.

Examples

import vipyr as vp
r = vp.features.sessions()                  # a synthetic table; pass df= for yours
print(r.frame.head())
assert r.check()

        session_start  session_index  secs_since_start  n_prev_in_session
0 2026-01-01 18:18:09              0               0.0                  0
1 2026-01-02 08:52:12              1               0.0                  0
2 2026-01-03 00:05:53              2               0.0                  0
3 2026-01-03 03:36:31              3               0.0                  0
4 2026-01-04 23:55:26              4               0.0                  0

Each example ran as written when these pages were generated, and the output shown is what it printed.

Checked against

Reference: catalog.sessions_reference: a pandas groupby().apply() with a Python loop per row, equal bit for bit; vipyr.check_point_in_time: no feature reads a row after its own time

Source

Viv: catalog/sessions.viv
Viv: catalog/catalog.py
The defs it reaches and the calls between them: map of the code