如何将持续时间转换为极坐标中的数字？

Question

polars

中是否有任何内置函数或更好的方法通过定义时间分辨率（例如：天、小时、分钟）将持续时间转换为数字？

import polars as pl

df = pl.DataFrame({
    "from": ["2023-01-01", "2023-01-02", "2023-01-03"],
    "to": ["2023-01-04", "2023-01-05", "2023-01-06"],
})

我目前的做法：

# Convert to date and calculate the time difference
df = (
    df.with_columns(
        pl.col("to", "from").str.to_date().name.suffix("_date")
    )
    .with_columns((pl.col("to_date") - pl.col("from_date")).alias("time_diff"))
)

# Convert the time difference to int (in days)
df = df.with_columns(
    ((pl.col("time_diff") / (24 * 60 * 60 * 1000)).cast(pl.Int8)).alias("time_diff_int")
)

输出：

shape: (3, 6)
┌────────────┬────────────┬────────────┬────────────┬──────────────┬───────────────┐
│ from       ┆ to         ┆ to_date    ┆ from_date  ┆ time_diff    ┆ time_diff_int │
│ ---        ┆ ---        ┆ ---        ┆ ---        ┆ ---          ┆ ---           │
│ str        ┆ str        ┆ date       ┆ date       ┆ duration[ms] ┆ i8            │
╞════════════╪════════════╪════════════╪════════════╪══════════════╪═══════════════╡
│ 2023-01-01 ┆ 2023-01-04 ┆ 2023-01-04 ┆ 2023-01-01 ┆ 3d           ┆ 3             │
│ 2023-01-02 ┆ 2023-01-05 ┆ 2023-01-05 ┆ 2023-01-02 ┆ 3d           ┆ 3             │
│ 2023-01-03 ┆ 2023-01-06 ┆ 2023-01-06 ┆ 2023-01-03 ┆ 3d           ┆ 3             │
└────────────┴────────────┴────────────┴────────────┴──────────────┴───────────────┘

Answer 1

dt

访问器可让您获取单独的组件，这就是您正在寻找的吗？

df["time_diff"].dt.days()
Series: 'time_diff' [i64]
[
    3
    3
    3
]

df["time_diff"].dt.hours()
Series: 'time_diff' [i64]
[
    72
    72
    72
]

df["time_diff"].dt.minutes()
Series: 'time_diff' [i64]
[
    4320
    4320
    4320
]

文档：API参考，系列/时间序列