Method restrict

python/pathway/internals/table.py:1087–1136

Restrict self universe to keys appearing in other. Args: other: table which universe is used to restrict universe of self. Returns: Table: table with restricted universe, with the same set of columns Example: >>> import pathway as pw

(self, other: TableLike)

    @trace_user_frame
    @check_arg_types
    def restrict(self, other: TableLike) -> Table[TSchema]:
        """Restrict self universe to keys appearing in other.

        Args:
            other: table which universe is used to restrict universe of self.

        Returns:
            Table: table with restricted universe, with the same set of columns


        Example:

        >>> import pathway as pw
        >>> t1 = pw.debug.table_from_markdown(
        ...     '''
        ...   | age  | owner  | pet
        ... 1 | 10   | Alice  | 1
        ... 2 | 9    | Bob    | 1
        ... 3 | 8    | Alice  | 2
        ... '''
        ... )
        >>> t2 = pw.debug.table_from_markdown(
        ...     '''
        ...   | cost
        ... 2 | 100
        ... 3 | 200
        ... '''
        ... )
        >>> t2.promise_universe_is_subset_of(t1)
        <pathway.Table schema={'cost': <class 'int'>}>
        >>> t3 = t1.restrict(t2)
        >>> pw.debug.compute_and_print(t3, include_id=False)
        age | owner | pet
        8   | Alice | 2
        9   | Bob   | 1
        """
        if self._universe == other._universe:
            warnings.warn("Identical universes for Table.restrict().", stacklevel=5)
            return self
        if not other._universe.is_subset_of(self._universe):
            raise ValueError(
                "Table.restrict(): other universe has to be a subset of self universe."
                + "Consider using Table.promise_universe_is_subset_of() to assert it."
            )
        if other._universe.is_equal_to(self._universe):
            warnings.warn(
                "Unnecessary call to Table.restrict(), consider using Table.with_universe_of().",
                stacklevel=5,
            )
        return self._restrict(other)

    @contextualized_operator
    def _restrict(self, other: TableLike) -> Table[TSchema]: