polars pivot for dataframe

Pivot a DataFrame from long to wide format.

Signature

> polars pivot {flags}

Flags

  • --on, -o {list<string>}: Column names for pivoting.
  • --index, -i {list<string>}: Column names for indexes.
  • --values, -v {list<string>}: Column names used as value columns.
  • --aggregate, -a {any}: Aggregation to apply when pivoting. The following are supported: first, sum, min, max, mean, median, count, last, or a custom expression.
  • --separator, -p {string}: Delimiter in generated column names in case of multiple values columns (default '_').
  • --sort, -s: Sort columns.
  • --streamable, -t: Whether or not to use the polars streaming engine. Only valid for lazy dataframes.
  • --stable: Perform a stable pivot.

Input/output types:

inputoutput
polars_dataframepolars_dataframe
polars_lazyframepolars_lazyframe

Examples

Perform a pivot in order to show individuals test score by subject

> [[name subject date test_1 test_2]; [Cady maths 2025-04-01 98 100] [Cady physics 2025-04-01 99 100] [Karen maths 2025-04-02 61 60] [Karen physics 2025-04-02 58 60]] | polars into-df |  polars pivot --on [subject] --index [name date] --values [test_1]
╭───┬───────┬───────────────┬───────┬─────────╮
│ # │ name  │     date      │ maths │ physics │
├───┼───────┼───────────────┼───────┼─────────┤
│ 0 │ Cady  │ 11 months ago │    98 │      99 │
│ 1 │ Karen │ 11 months ago │    61 │      58 │
╰───┴───────┴───────────────┴───────┴─────────╯

Perform a pivot with multiple values columns with a separator

> [[name subject date test_1 test_2 grade_1 grade_2]; [Cady maths 2025-04-01 98 100 A A] [Cady physics 2025-04-01 99 100 A A] [Karen maths 2025-04-02 61 60 D D] [Karen physics 2025-04-02 58 60 D D]] | polars into-df |  polars pivot --on [subject] --index [name] --values [test_1 grade_1] --separator /
╭───┬───────┬──────────────┬────────────────┬───────────────┬─────────────────╮
│ # │ name  │ test_1/maths │ test_1/physics │ grade_1/maths │ grade_1/physics │
├───┼───────┼──────────────┼────────────────┼───────────────┼─────────────────┤
│ 0 │ Cady  │           98 │             99 │ A             │ A               │
│ 1 │ Karen │           61 │             58 │ D             │ D               │
╰───┴───────┴──────────────┴────────────────┴───────────────┴─────────────────╯