week()#

relationalai.std.dates
#week(date: date|datetime|Producer, tz: str|Producer = "UTC") -> Expression

Computes the ISO week number (1–53) from a date or UTC datetime value. If tz is specified, then date is converted from UTC to the specified timezone before extracting the week number. tz is ignored if date is a Python date or datetime object. If any of the arguments are Producer objects, then week() also acts as a filter and removes invalid values from the producer. Must be called in a rule or query context.

Parameters#

NameTypeDescription
dateProducer or Python date or datetime objectThe date or datetime value from which to extract the week number.
tzProducer or Python str objectOptional timezone string (e.g., "America/New_York"), offset string (e.g., "+0600"), or Python tzinfo object. Refer to the timezone database for a list of valid timezone identifiers. Ignored if date is a Python date or datetime object. (Default: "UTC").

Returns#

An Expression object.

Raises#

TypeError if the date parameter is not a Producer object or Python date or datetime object.

Example#

Use week() to extract the ISO week number component from date and datetime values:

##
import relationalai as rai
from relationalai.std import alias, dates


# =====
# SETUP
# =====

model = rai.Model("MyModel")
Event = model.Type("Event")

with model.rule():
    Event.add(id=1).set(time=dates.datetime(2024, 1, 1, 1, 30))
    Event.add(id=2).set(time="invalid")


# =======
# EXAMPLE
# =======

with model.rule():
    event = Event()
    # week() filters out any events with invalid time values, so the
    # following only sets the week property for Event 1.
    event.set(week=dates.week(event.time))
    # Since Event 2 is filtered out above, the following only sets the
    # has_valid_time property for Event 1.
    event.set(has_valid_time=True)

with model.query() as select:
    event = Event()
    response = select(event.id, event.time, event.week, event.has_valid_time)

print(response.results)
#    id                 time  week has_valid_time
# 0   1  2024-01-01 01:30:00   1.0           True
# 1   2              invalid   NaN            NaN

If the date parameter is a datetime and the tz parameter is specified, the datetime is converted from UTC to the specified timezone before computing the weekday:

#with model.query() as select:
    event = Event()
    week1 = dates.week(event.time, tz="America/New_York")
    week2 = dates.week(event.time, tz="+0600")
    response = select(event.id, event.time, alias(week1, "week1"), alias(week2, "week2"))

print(response.results)
#    id                time  week1  week2
# 0   1 2024-01-01 01:30:00     52      1

See Also#