polars.Expr.dt.combine#

Expr.dt.combine(tm: time | Expr, tu: TimeUnit = 'us') Expr[source]#

Create a naive Datetime from an existing Date/Datetime expression and a Time.

If the underlying expression is a Datetime then its time component is replaced, and if it is a Date then a new Datetime is created by combining the two values.

Parameters:
tm

A python time literal or polars expression/column that resolves to a time.

tu{‘ns’, ‘us’, ‘ms’}

Time unit.

Examples

>>> from datetime import datetime, date, time
>>> df = pl.DataFrame(
...     {
...         "dtm": [
...             datetime(2022, 12, 31, 10, 30, 45),
...             datetime(2023, 7, 5, 23, 59, 59),
...         ],
...         "dt": [date(2022, 10, 10), date(2022, 7, 5)],
...         "tm": [time(1, 2, 3, 456000), time(7, 8, 9, 101000)],
...     }
... )
>>> df
shape: (2, 3)
┌─────────────────────┬────────────┬──────────────┐
│ dtm                 ┆ dt         ┆ tm           │
│ ---                 ┆ ---        ┆ ---          │
│ datetime[μs]        ┆ date       ┆ time         │
╞═════════════════════╪════════════╪══════════════╡
│ 2022-12-31 10:30:45 ┆ 2022-10-10 ┆ 01:02:03.456 │
│ 2023-07-05 23:59:59 ┆ 2022-07-05 ┆ 07:08:09.101 │
└─────────────────────┴────────────┴──────────────┘
>>> df.select(
...     [
...         pl.col("dtm").dt.combine(pl.col("tm")).alias("d1"),
...         pl.col("dt").dt.combine(pl.col("tm")).alias("d2"),
...         pl.col("dt").dt.combine(time(4, 5, 6)).alias("d3"),
...     ]
... )
shape: (2, 3)
┌─────────────────────────┬─────────────────────────┬─────────────────────┐
│ d1                      ┆ d2                      ┆ d3                  │
│ ---                     ┆ ---                     ┆ ---                 │
│ datetime[μs]            ┆ datetime[μs]            ┆ datetime[μs]        │
╞═════════════════════════╪═════════════════════════╪═════════════════════╡
│ 2022-12-31 01:02:03.456 ┆ 2022-10-10 01:02:03.456 ┆ 2022-10-10 04:05:06 │
│ 2023-07-05 07:08:09.101 ┆ 2022-07-05 07:08:09.101 ┆ 2022-07-05 04:05:06 │
└─────────────────────────┴─────────────────────────┴─────────────────────┘