Retrieve date from datetime column in polars

Question

Currently when I try to retrieve date from a polars datetime column, I have to write something similar to:

import polars as pl
import datetime as dt

df = pl.DataFrame({
    'time': [dt.datetime.now()]
})

df = df.with_columns(
    pl.col("time").map_elements(lambda x: x.date()).alias("date")
)

shape: (1, 2)
┌────────────────────────────┬────────────┐
│ time                       ┆ date       │
│ ---                        ┆ ---        │
│ datetime[μs]               ┆ date       │
╞════════════════════════════╪════════════╡
│ 2024-07-20 11:41:04.265539 ┆ 2024-07-20 │
└────────────────────────────┴────────────┘

Is there a different way, something closer to:

pl.col("time").dt.date().alias("date")

Answer 1

You can use .dt.date()

import datetime
import polars as pl

df = pl.DataFrame({
    "time": [datetime.datetime.now()]
})

df.with_columns(
    pl.col("time").dt.date().alias("date")
)

shape: (1, 2)
┌────────────────────────────┬────────────┐
│ time                       ┆ date       │
│ ---                        ┆ ---        │
│ datetime[μs]               ┆ date       │
╞════════════════════════════╪════════════╡
│ 2024-07-21 16:17:41.489579 ┆ 2024-07-21 │
└────────────────────────────┴────────────┘