{"record":{"id":"75fcb7462253ff5b","repo":"pola-rs/polars","slug":"enum-categories-must-be-unique-found-duplicate-d","errorCode":null,"errorMessage":"Enum categories must be unique; found duplicate {duplicate!r}","messagePattern":"Enum categories must be unique; found duplicate (.+?)","errorType":"exception","errorClass":"ValueError","httpStatus":null,"severity":"error","filePath":"py-polars/src/polars/datatypes/classes.py","lineNumber":1070,"sourceCode":"        elif not isinstance(categories, pl.Series):\n            categories = pl.Series(values=categories)\n\n        if categories.is_empty():\n            self.categories = pl.Series(name=\"category\", dtype=String)\n            return\n\n        if categories.has_nulls():\n            msg = \"Enum categories must not contain null values\"\n            raise TypeError(msg)\n\n        if (dtype := categories.dtype) != String:\n            msg = f\"Enum categories must be strings; found data of type {dtype}\"\n            raise TypeError(msg)\n\n        if categories.n_unique() != categories.len():\n            duplicate = categories.filter(categories.is_duplicated())[0]\n            msg = f\"Enum categories must be unique; found duplicate {duplicate!r}\"\n            raise ValueError(msg)\n\n        self.categories = categories.rechunk().alias(\"category\")\n\n    def __eq__(self, other: PolarsDataType) -> bool:  # type: ignore[override]\n        # allow comparing object instances to class\n        if type(other) is DataTypeClass and issubclass(other, Enum):\n            return True\n        elif isinstance(other, Enum):\n            return self.categories.equals(other.categories)\n        else:\n            return False\n\n    def __hash__(self) -> int:\n        return hash((self.__class__, tuple(self.categories)))\n\n    def __repr__(self) -> str:\n        class_name = self.__class__.__name__\n        return f\"{class_name}(categories={self.categories.to_list()!r})\"","sourceCodeStart":1052,"sourceCodeEnd":1088,"githubUrl":"https://github.com/pola-rs/polars/blob/df599052daf96e7a9cc30a3b0c6bd25d6947e3c0/py-polars/src/polars/datatypes/classes.py#L1052-L1088","documentation":"Error \"Enum categories must be unique; found duplicate {duplicate!r}\" thrown in pola-rs/polars.","triggerScenarios":"Thrown at py-polars/src/polars/datatypes/classes.py:1070 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":[],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"df599052daf96e7a9cc30a3b0c6bd25d6947e3c0","analyzedAt":"2026-08-16T12:10:03.978Z","schemaVersion":2},"datasetVersion":"2026-08-16T13:17:31.715Z"}