polars.duration#

polars.duration( *, weeks: Expr | str | int | None = None, days: Expr | str | int | None = None, hours: Expr | str | int | None = None, minutes: Expr | str | int | None = None, seconds: Expr | str | int | None = None, milliseconds: Expr | str | int | None = None, microseconds: Expr | str | int | None = None, nanoseconds: Expr | str | int | None = None, time_unit: TimeUnit = 'us', ) → Expr[source]#

Create polars Duration from distinct time components.

Parameters:

weeks: Number of weeks.
days: Number of days.
hours: Number of hours.
minutes: Number of minutes.
seconds: Number of seconds.
milliseconds: Number of milliseconds.
microseconds: Number of microseconds.
nanoseconds: Number of nanoseconds.
time_unit{‘us’, ‘ms’, ‘ns’}: Time unit of the resulting expression.

Returns:

Expr: Expression of data type Duration.

Notes

A duration represents a fixed amount of time. For example, pl.duration(days=1) means “exactly 24 hours”. By contrast, Expr.dt.offset_by('1d') means “1 calendar day”, which could sometimes be 23 hours or 25 hours depending on Daylight Savings Time. For non-fixed durations such as “calendar month” or “calendar day”, please use polars.Expr.dt.offset_by() instead.

Examples

>>> from datetime import datetime
>>> df = pl.DataFrame(
...     {
...         "dt": [datetime(2022, 1, 1), datetime(2022, 1, 2)],
...         "add": [1, 2],
...     }
... )
>>> df
shape: (2, 2)
┌─────────────────────┬─────┐
│ dt                  ┆ add │
│ ---                 ┆ --- │
│ datetime[μs]        ┆ i64 │
╞═════════════════════╪═════╡
│ 2022-01-01 00:00:00 ┆ 1   │
│ 2022-01-02 00:00:00 ┆ 2   │
└─────────────────────┴─────┘
>>> with pl.Config(tbl_width_chars=120):
...     df.select(
...         (pl.col("dt") + pl.duration(weeks="add")).alias("add_weeks"),
...         (pl.col("dt") + pl.duration(days="add")).alias("add_days"),
...         (pl.col("dt") + pl.duration(seconds="add")).alias("add_seconds"),
...         (pl.col("dt") + pl.duration(milliseconds="add")).alias("add_millis"),
...         (pl.col("dt") + pl.duration(hours="add")).alias("add_hours"),
...     )
...
shape: (2, 5)
┌─────────────────────┬─────────────────────┬─────────────────────┬─────────────────────────┬─────────────────────┐
│ add_weeks           ┆ add_days            ┆ add_seconds         ┆ add_millis              ┆ add_hours           │
│ ---                 ┆ ---                 ┆ ---                 ┆ ---                     ┆ ---                 │
│ datetime[μs]        ┆ datetime[μs]        ┆ datetime[μs]        ┆ datetime[μs]            ┆ datetime[μs]        │
╞═════════════════════╪═════════════════════╪═════════════════════╪═════════════════════════╪═════════════════════╡
│ 2022-01-08 00:00:00 ┆ 2022-01-02 00:00:00 ┆ 2022-01-01 00:00:01 ┆ 2022-01-01 00:00:00.001 ┆ 2022-01-01 01:00:00 │
│ 2022-01-16 00:00:00 ┆ 2022-01-04 00:00:00 ┆ 2022-01-02 00:00:02 ┆ 2022-01-02 00:00:00.002 ┆ 2022-01-02 02:00:00 │
└─────────────────────┴─────────────────────┴─────────────────────┴─────────────────────────┴─────────────────────┘

If you need to add non-fixed durations, you should use polars.Expr.dt.offset_by() instead:

>>> with pl.Config(tbl_width_chars=120):
...     df.select(
...         add_calendar_days=pl.col("dt").dt.offset_by(
...             pl.format("{}d", pl.col("add"))
...         ),
...         add_calendar_months=pl.col("dt").dt.offset_by(
...             pl.format("{}mo", pl.col("add"))
...         ),
...         add_calendar_years=pl.col("dt").dt.offset_by(
...             pl.format("{}y", pl.col("add"))
...         ),
...     )
...
shape: (2, 3)
┌─────────────────────┬─────────────────────┬─────────────────────┐
│ add_calendar_days   ┆ add_calendar_months ┆ add_calendar_years  │
│ ---                 ┆ ---                 ┆ ---                 │
│ datetime[μs]        ┆ datetime[μs]        ┆ datetime[μs]        │
╞═════════════════════╪═════════════════════╪═════════════════════╡
│ 2022-01-02 00:00:00 ┆ 2022-02-01 00:00:00 ┆ 2023-01-01 00:00:00 │
│ 2022-01-04 00:00:00 ┆ 2022-03-02 00:00:00 ┆ 2024-01-02 00:00:00 │
└─────────────────────┴─────────────────────┴─────────────────────┘