col

function

def col(
    name: str | PolarsDataType | PythonDataType | Iterable[str] | Iterable[PolarsDataType | PythonDataType],
    *more_names: str | PolarsDataType | PythonDataType = (),
) -> Expr

Categories: projection

Reference one or more columns as an expression.

The returned Expr is the building block passed to select, with_columns, filter and agg.

Parameters

parameter

namestr | PolarsDataType | PythonDataType | Iterable[str] | Iterable[PolarsDataType | PythonDataType] (str | DataType | type[int] | type[float] | type[bool] | type[str] | type[date] | type[time] | type[datetime] | type[timedelta] | type[list[Any]] | type[tuple[Any, ...]] | type[bytes] | type[object] | type[Decimal] | type[None] | Iterable[str] | Iterable[DataType | type[int] | type[float] | type[bool] | type[str] | type[date] | type[time] | type[datetime] | type[timedelta] | type[list[Any]] | type[tuple[Any, ...]] | type[bytes] | type[object] | type[Decimal] | type[None]])

A column name, a data type (to select every column of that type), or an iterable of either. A name wrapped in ^ and $ is treated as a regular expression.

parameter

*more_namesstr | PolarsDataType | PythonDataType (str | DataType | type[int] | type[float] | type[bool] | type[str] | type[date] | type[time] | type[datetime] | type[timedelta] | type[list[Any]] | type[tuple[Any, ...]] | type[bytes] | type[object] | type[Decimal] | type[None])

Additional column names or data types, as positional arguments.

Examples

tf.select(col("a"), (col("b") * 2).alias("b2"))
tf.filter(col("g").is_in(["x", "y"]))