Method pointer_from

python/pathway/internals/table.py:2633–2659

Pseudo-random hash of its argument. Produces pointer types. Applied column-wise. Example: >>> import pathway as pw >>> t1 = pw.debug.table_from_markdown(''' ... age owner pet ... 1 10 Alice dog ... 2 9 Bob dog ... 3 8 Alic

(
        self, *args: Any, optional=False, instance: expr.ColumnReference | None = None
    )

    @trace_user_frame
    def pointer_from(
        self, *args: Any, optional=False, instance: expr.ColumnReference | None = None
    ):
        """Pseudo-random hash of its argument. Produces pointer types. Applied column-wise.

        Example:

        >>> import pathway as pw
        >>> t1 = pw.debug.table_from_markdown('''
        ...    age  owner  pet
        ... 1   10  Alice  dog
        ... 2    9    Bob  dog
        ... 3    8  Alice  cat
        ... 4    7    Bob  dog''')
        >>> g = t1.groupby(t1.owner).reduce(refcol = t1.pointer_from(t1.owner)) # g.id == g.refcol
        >>> pw.debug.compute_and_print(g.select(test = (g.id == g.refcol)), include_id=False)
        test
        True
        True
        """
        # XXX verify types for the table primary_keys
        return expr.PointerExpression(
            self,
            *args,
            instance=instance,
            optional=optional,
        )

    @trace_user_frame
    def ix_ref(