polars unpivot for dataframe

Unpivot a DataFrame from wide to long format.

This command requires a plugin

The polars unpivot command resides in the polars plugin. To use this command, you must install and register nu_plugin_polars. See the Plugins chapter in the book for more information.

Signature

> polars unpivot {flags}

Flags

  • --index, -i {list<any>}: column names for unpivoting
  • --on, -o {list<any>}: column names used as value columns
  • --variable-name, -r {string}: optional name for variable column
  • --value-name, -l {string}: optional name for value column

Input/output types:

inputoutput
dataframedataframe

Examples

unpivot on an eager dataframe

> [[a b c d]; [x 1 4 a] [y 2 5 b] [z 3 6 c]] | polars into-df | polars unpivot -i [b c] -o [a d]
╭───┬───┬───┬──────────┬───────╮
│ # │ b │ c │ variable │ value │
├───┼───┼───┼──────────┼───────┤
│ 0 │ 1 │ 4 │ a        │ x     │
│ 1 │ 2 │ 5 │ a        │ y     │
│ 2 │ 3 │ 6 │ a        │ z     │
│ 3 │ 1 │ 4 │ d        │ a     │
│ 4 │ 2 │ 5 │ d        │ b     │
│ 5 │ 3 │ 6 │ d        │ c     │
╰───┴───┴───┴──────────┴───────╯

unpivot on a lazy dataframe

> [[a b c d]; [x 1 4 a] [y 2 5 b] [z 3 6 c]] | polars into-lazy | polars unpivot -i [b c] -o [a d] | polars collect
╭───┬───┬───┬──────────┬───────╮
│ # │ b │ c │ variable │ value │
├───┼───┼───┼──────────┼───────┤
│ 0 │ 1 │ 4 │ a        │ x     │
│ 1 │ 2 │ 5 │ a        │ y     │
│ 2 │ 3 │ 6 │ a        │ z     │
│ 3 │ 1 │ 4 │ d        │ a     │
│ 4 │ 2 │ 5 │ d        │ b     │
│ 5 │ 3 │ 6 │ d        │ c     │
╰───┴───┴───┴──────────┴───────╯