Method from_columns

python/pathway/internals/table.py:272–311

Build a table from columns. All columns must have the same ids. Columns' names must be pairwise distinct. Args: args: List of columns. kwargs: Columns with their new names. Returns: Table: Created table. Example: >>> i

(
        *args: expr.ColumnReference, **kwargs: expr.ColumnReference
    )

    @staticmethod
    @check_arg_types
    def from_columns(
        *args: expr.ColumnReference, **kwargs: expr.ColumnReference
    ) -> Table:
        """Build a table from columns.

        All columns must have the same ids. Columns' names must be pairwise distinct.

        Args:
            args: List of columns.
            kwargs: Columns with their new names.

        Returns:
            Table: Created table.


        Example:

        >>> import pathway as pw
        >>> t1 = pw.Table.empty(age=float, pet=float)
        >>> t2 = pw.Table.empty(foo=float, bar=float).with_universe_of(t1)
        >>> t3 = pw.Table.from_columns(t1.pet, qux=t2.foo)
        >>> pw.debug.compute_and_print(t3, include_id=False)
        pet | qux
        """
        all_args = cast(
            dict[str, expr.ColumnReference], combine_args_kwargs(args, kwargs)
        )
        if not all_args:
            raise ValueError("Table.from_columns() cannot have empty arguments list")
        else:
            arg = next(iter(all_args.values()))
            table: Table = arg.table
            for arg in all_args.values():
                if not table._universe.is_equal_to(arg.table._universe):
                    raise ValueError(
                        "Universes of all arguments of Table.from_columns() have to be equal.\n"
                        + "Consider using Table.promise_universes_are_equal() to assert it.\n"
                        + "(However, untrue assertion might result in runtime errors.)"
                    )
            return table.select(*args, **kwargs)

    @trace_user_frame
    @check_arg_types