polars.LazyFrame.collect#

LazyFrame.collect( *, type_coercion: bool = True, predicate_pushdown: bool = True, projection_pushdown: bool = True, simplify_expression: bool = True, no_optimization: bool = False, slice_pushdown: bool = True, comm_subplan_elim: bool = True, comm_subexpr_elim: bool = True, streaming: bool = False, ) → DataFrame[source]#

Collect into a DataFrame.

Note: use fetch() if you want to run your query on the first n rows only. This can be a huge time saver in debugging queries.

Parameters:

type_coercion: Do type coercion optimization.
predicate_pushdown: Do predicate pushdown optimization.
projection_pushdown: Do projection pushdown optimization.
simplify_expression: Run simplify expressions optimization.
no_optimization: Turn off (certain) optimizations.
slice_pushdown: Slice pushdown optimization.
comm_subplan_elim: Will try to cache branching subplans that occur on self-joins or unions.
comm_subexpr_elim: Common subexpressions will be cached and reused.
streaming: Run parts of the query in a streaming fashion (this is in an alpha state)

Returns:

DataFrame

Examples

>>> lf = pl.LazyFrame(
...     {
...         "a": ["a", "b", "a", "b", "b", "c"],
...         "b": [1, 2, 3, 4, 5, 6],
...         "c": [6, 5, 4, 3, 2, 1],
...     }
... )
>>> lf.groupby("a", maintain_order=True).agg(pl.all().sum()).collect()
shape: (3, 3)
┌─────┬─────┬─────┐
│ a   ┆ b   ┆ c   │
│ --- ┆ --- ┆ --- │
│ str ┆ i64 ┆ i64 │
╞═════╪═════╪═════╡
│ a   ┆ 4   ┆ 10  │
│ b   ┆ 11  ┆ 10  │
│ c   ┆ 6   ┆ 1   │
└─────┴─────┴─────┘