polars.select#

polars.select(
*exprs: IntoExpr | Iterable[IntoExpr],
eager: bool = True,
**named_exprs: IntoExpr,
) → DataFrame | LazyFrame[source]#

Run polars expressions without a context.

This is syntactic sugar for running df.select on an empty DataFrame (or LazyFrame if eager=False).

Parameters:
*exprs

Column(s) to select, specified as positional arguments. Accepts expression input. Strings are parsed as column names, other non-expression inputs are parsed as literals.

eager

Evaluate immediately and return a DataFrame (default); if set to False, return a LazyFrame instead.

**named_exprs

Additional columns to select, specified as keyword arguments. The columns will be renamed to the keyword used.

Returns:
DataFrame or LazyFrame

Examples

>>> foo = pl.Series("foo", [1, 2, 3])
>>> bar = pl.Series("bar", [3, 2, 1])
>>> pl.select(min=pl.min_horizontal(foo, bar))
shape: (3, 1)
┌─────┐
│ min │
│ --- │
│ i64 │
╞═════╡
│ 1   │
│ 2   │
│ 1   │
└─────┘

>>> pl.select(pl.int_range(0, 100_000, 2).alias("n"), eager=False).filter(
...     pl.col("n") % 22_500 == 0
... ).collect()
shape: (5, 1)
┌───────┐
│ n     │
│ ---   │
│ i64   │
╞═══════╡
│ 0     │
│ 22500 │
│ 45000 │
│ 67500 │
│ 90000 │
└───────┘
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