Method update_cells

python/pathway/internals/table.py:1691–1754

Updates cells of `self`, breaking ties in favor of the values in `other`. Semantics: - result.columns == self.columns - result.id == self.id - conflicts are resolved preferring other's values Requires: - other.columns ⊆ self.columns

(self, other: Table, _stacklevel: int = 1)

    @trace_user_frame
    @check_arg_types
    def update_cells(self, other: Table, _stacklevel: int = 1) -> Table:
        """Updates cells of `self`, breaking ties in favor of the values in `other`.

        Semantics:
            - result.columns == self.columns
            - result.id == self.id
            - conflicts are resolved preferring other's values

        Requires:
            - other.columns ⊆ self.columns
            - other.id ⊆ self.id

        Args:
            other:  the other table.

        Returns:
            Table: `self` updated with cells form `other`.

        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('''
        ...     age | owner | pet
        ... 1 | 10  | Alice | 30
        ... ''')
        >>> pw.universes.promise_is_subset_of(t2, t1)
        >>> t3 = t1.update_cells(t2)
        >>> pw.debug.compute_and_print(t3, include_id=False)
        age | owner | pet
        8   | Alice | 2
        9   | Bob   | 1
        10  | Alice | 30
        """
        if names := (set(other.keys()) - set(self.keys())):
            raise ValueError(
                f"Columns of the argument in Table.update_cells() not present in the updated table: {list(names)}."
            )

        if self._universe == other._universe:
            warnings.warn(
                "Key sets of self and other in update_cells are the same."
                + " Using with_columns instead of update_cells.",
                stacklevel=_stacklevel + 4,
            )
            return self.with_columns(*(other[name] for name in other))

        schema = {}
        for key in other.keys():
            schema[key] = _types_lca_with_error(
                self.schema._dtypes()[key],
                other.schema._dtypes()[key],
                function_name="an update_cells",