Set the alias for this reducer. ### Parameters - **alias**: The value of the alias for this reducer. If this is the special value `aggregation.FIELDNAME` then this reducer will be aliased using the same name as the field upon which it operates.
(self, alias: str)
| 32 | self._alias: Optional[str] = None |
| 33 | |
| 34 | def alias(self, alias: str) -> "Reducer": |
| 35 | """ |
| 36 | Set the alias for this reducer. |
| 37 | |
| 38 | ### Parameters |
| 39 | |
| 40 | - **alias**: The value of the alias for this reducer. If this is the |
| 41 | special value `aggregation.FIELDNAME` then this reducer will be |
| 42 | aliased using the same name as the field upon which it operates. |
| 43 | Note that using `FIELDNAME` is only possible on reducers which |
| 44 | operate on a single field value. |
| 45 | |
| 46 | This method returns the `Reducer` object making it suitable for |
| 47 | chaining. |
| 48 | """ |
| 49 | if alias is FIELDNAME: |
| 50 | if not self._field: |
| 51 | raise ValueError("Cannot use FIELDNAME alias with no field") |
| 52 | else: |
| 53 | # Chop off initial '@' |
| 54 | alias = self._field[1:] |
| 55 | self._alias = alias |
| 56 | return self |
| 57 | |
| 58 | @property |
| 59 | def args(self) -> Tuple[str, ...]: |
no outgoing calls