Method get

python/pathway/internals/expression.py:360–399

Extracts element at `index` from an object. The object has to be a Tuple or Json. If no element is present at `index`, it returns value specified by a `default` parameter. Index can be effectively `int` for Tuple and `int` or `str` for Json. For Tuples, using negative index

(
        self,
        index: ColumnExpression | int | str,
        default: ColumnExpression | Value = None,
    )

        return GetExpression(self, index, check_if_exists=False)

    def get(
        self,
        index: ColumnExpression | int | str,
        default: ColumnExpression | Value = None,
    ) -> ColumnExpression:
        """Extracts element at `index` from an object. The object has to be a Tuple or Json.
        If no element is present at `index`, it returns value specified by a `default` parameter.

        Index can be effectively `int` for Tuple and `int` or `str` for Json.
        For Tuples, using negative index can be used to access elements at the end, moving backwards.

        Args:
            index: Position to extract element at.
            default: Value returned when no element is at position `index`. Defaults to None.

        Example:

        >>> import pathway as pw
        >>> t1 = pw.debug.table_from_markdown(
        ...     '''
        ...   | a | b | c
        ... 1 | 3 | 2 | 2
        ... 2 | 4 | 1 | 0
        ... 3 | 7 | 3 | 1
        ... '''
        ... )
        >>> t2 = t1.with_columns(tup=pw.make_tuple(pw.this.a, pw.this.b))
        >>> t3 = t2.select(
        ...     x=pw.this.tup.get(1),
        ...     y=pw.this.tup.get(3),
        ...     z=pw.this.tup.get(pw.this.c),
        ...     t=pw.this.tup.get(pw.this.c, default=100),
        ... )
        >>> pw.debug.compute_and_print(t3, include_id=False)
        x | y | z | t
        1 |   | 4 | 4
        2 |   |   | 100
        3 |   | 3 | 3
        """
        return GetExpression(self, index, default, check_if_exists=True)

    @property
    def dt(self) -> DateTimeNamespace: