Polars groupby and rank by dates

Sleepy Sable answered on October 6, 2022 Popularity 1/10 Helpfulness 1/10

answer Polars groupby and rank by dates

Polars groupby and rank by dates

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import polars as pl
from datetime import date

df = pl.DataFrame(
    {
        "user": [1, 1, 1, 1, 1, 2, 2, 2, 2, 2],
        "date": [
            date(2015, 1, 11),
            date(2015, 1, 11),
            date(2015, 5, 8),
            date(2015, 7, 8),
            date(2016, 3, 18),
            date(2015, 2, 10),
            date(2015, 9, 8),
            date(2016, 1, 1),
            date(2016, 1, 1),
            date(2016, 3, 17),
        ],
    }
)

df = df.with_column(pl.col("date").
               rank(method="min").
               over(["user"]).alias("rank"))




>>> df
shape: (10, 3)
┌──────┬────────────┬──────┐
│ user ┆ date       ┆ rank │
│ ---  ┆ ---        ┆ ---  │
│ i64  ┆ date       ┆ u32  │
╞══════╪════════════╪══════╡
│ 1    ┆ 2015-01-11 ┆ 1    │
├╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┤
│ 1    ┆ 2015-01-11 ┆ 1    │
├╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┤
│ 1    ┆ 2015-05-08 ┆ 3    │
├╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┤
│ 1    ┆ 2015-07-08 ┆ 4    │
├╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┤
│ ...  ┆ ...        ┆ ...  │
├╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┤
│ 2    ┆ 2015-09-08 ┆ 2    │
├╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┤
│ 2    ┆ 2016-01-01 ┆ 3    │
├╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┤
│ 2    ┆ 2016-01-01 ┆ 3    │
├╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┤
│ 2    ┆ 2016-03-17 ┆ 5    │
└──────┴────────────┴──────┘

Popularity 1/10 Helpfulness 1/10 Language python

Source: stackoverflow.com

Tags: group-by python rank

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Contributed on Oct 06 2022

Sleepy Sable

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Polars groupby and rank by dates

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