DateValue

DateValue(arg)

Attributes

Name	Description
add	Add an interval to a date.
radd	Add an interval to a date.
sub	Subtract a date or an interval from a date.

Methods

Name	Description
delta	Compute the number of `part`s between two dates.
epoch_days	Return the number of days since the UNIX epoch date.
strftime	Format a date according to `format_str`.
truncate	Truncate date expression to units of `unit`.

delta

delta(other, part)

Compute the number of parts between two dates.

The order of operands matches standard subtraction

The second argument is subtracted from the first.

Parameters

Name	Type	Description	Default
other	datetime.date \| Value[dt.Date]	A date expression	required
part	Literal['year', 'quarter', 'month', 'week', 'day'] \| Value[dt.String]	The unit of time to compute the difference in	required

Returns

Name	Type	Description
	IntegerValue	The number of `part`s between `self` and `other`

Examples

>>> import ibis
>>> ibis.options.interactive = True
>>> start = ibis.date("1992-09-30")
>>> end = ibis.date("1992-10-01")
>>> end.delta(start, unit="day")

┌───┐
│ 1 │
└───┘

>>> prez = ibis.examples.presidential.fetch()
>>> prez.mutate(
...     years_in_office=prez.end.delta(prez.start, unit="year"),
...     hours_in_office=prez.end.delta(prez.start, unit="hour"),
... ).drop("party")

┏━━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━┓
┃ name       ┃ start      ┃ end        ┃ years_in_office ┃ hours_in_office ┃
┡━━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━┩
│ string     │ date       │ date       │ int64           │ int64           │
├────────────┼────────────┼────────────┼─────────────────┼─────────────────┤
│ Eisenhower │ 1953-01-20 │ 1961-01-20 │               8 │           70128 │
│ Kennedy    │ 1961-01-20 │ 1963-11-22 │               2 │           24864 │
│ Johnson    │ 1963-11-22 │ 1969-01-20 │               6 │           45264 │
│ Nixon      │ 1969-01-20 │ 1974-08-09 │               5 │           48648 │
│ Ford       │ 1974-08-09 │ 1977-01-20 │               3 │           21480 │
│ Carter     │ 1977-01-20 │ 1981-01-20 │               4 │           35064 │
│ Reagan     │ 1981-01-20 │ 1989-01-20 │               8 │           70128 │
│ Bush       │ 1989-01-20 │ 1993-01-20 │               4 │           35064 │
│ Clinton    │ 1993-01-20 │ 2001-01-20 │               8 │           70128 │
│ Bush       │ 2001-01-20 │ 2009-01-20 │               8 │           70128 │
│ …          │ …          │ …          │               … │               … │
└────────────┴────────────┴────────────┴─────────────────┴─────────────────┘

epoch_days

epoch_days()

Return the number of days since the UNIX epoch date.

Examples

>>> import ibis
>>> ibis.options.interactive = True
>>> date = ibis.date(2020, 1, 1)
>>> date

┌────────────┐
│ 2020-01-01 │
└────────────┘

>>> date.epoch_days()

┌───────┐
│ 18262 │
└───────┘

>>> t = date.name("date_col").as_table()
>>> t

┏━━━━━━━━━━━━┓
┃ date_col   ┃
┡━━━━━━━━━━━━┩
│ date       │
├────────────┤
│ 2020-01-01 │
└────────────┘

>>> t.mutate(epoch=t.date_col.epoch_days())

┏━━━━━━━━━━━━┳━━━━━━━┓
┃ date_col   ┃ epoch ┃
┡━━━━━━━━━━━━╇━━━━━━━┩
│ date       │ int64 │
├────────────┼───────┤
│ 2020-01-01 │ 18262 │
└────────────┴───────┘

strftime

strftime(format_str)

Format a date according to format_str.

Format string may depend on the backend, but we try to conform to ANSI strftime.

Parameters

Name	Type	Description	Default
format_str	str	`strftime` format string	required

Returns

Name	Type	Description
	StringValue	Formatted version of `arg`

truncate

truncate(unit)

Truncate date expression to units of unit.

Parameters

Name	Type	Description	Default
unit	Literal['Y', 'Q', 'M', 'W', 'D']	Unit to truncate `arg` to	required

Returns

Name	Type	Description
	DateValue	Truncated date value expression