nushell/crates/nu_plugin_polars
pyz4 2dc5c19b71
feat(polars): loosen constraints on accepted expressions in polars group-by (#15583)
# Description
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This PR lifts the constraint that expressions in the `polars group-by`
command must be limited only to the type `Expr::Column` rather than most
`Expr` types, which is what the underlying polars crate allows. This
change enables more complex expressions to group by.

In the example below, we group by even or odd days of column `a`. While
we can reach the same result by creating and grouping by a new column in
two separate steps, integrating these steps in a single group-by allows
for better delegation to the polars optimizer.

```nushell
#  Group by an expression and perform an aggregation
  > [[a b]; [2025-04-01 1] [2025-04-02 2] [2025-04-03 3] [2025-04-04 4]]
    | polars into-lazy
    | polars group-by (polars col a | polars get-day | $in mod 2)
    | polars agg [
        (polars col b | polars min | polars as "b_min")
        (polars col b | polars max | polars as "b_max")
        (polars col b | polars sum | polars as "b_sum")
     ]
    | polars collect
    | polars sort-by a
  ╭───┬───┬───────┬───────┬───────╮
  │ # │ a │ b_min │ b_max │ b_sum │
  ├───┼───┼───────┼───────┼───────┤
  │ 0 │ 0 │     2 │     4 │     6 │
  │ 1 │ 1 │     1 │     3 │     4 │
  ╰───┴───┴───────┴───────┴───────╯
```  

# User-Facing Changes
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No breaking changes. The user is empowered to use more complex
expressions in `polars group-by`

# Tests + Formatting
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An example is added to `polars group-by`.

# After Submitting
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2025-04-16 14:18:48 -07:00
..
src feat(polars): loosen constraints on accepted expressions in polars group-by (#15583) 2025-04-16 14:18:48 -07:00
Cargo.toml build(deps): bump indexmap from 2.8.0 to 2.9.0 (#15531) 2025-04-09 13:15:29 +08:00
LICENSE Move dataframes support to a plugin (#12220) 2024-04-09 19:31:43 -05:00