테이블 형태 변경 (long to wide)에서 질문이

강의보면서 똑같이 no2 = air_quality[air_quality['parameter'] == 'no2'] 입력하니까 오류가 아래처럼 나오는데 어떻게 하나요?

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KeyError                                  Traceback (most recent call last)

/usr/local/lib/python3.10/dist-packages/pandas/core/indexes/base.py in get_loc(self, key, method, tolerance)
   3801             try:
-> 3802                 return self._engine.get_loc(casted_key)
   3803             except KeyError as err:

4 frames

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

KeyError: 'parameter'

The above exception was the direct cause of the following exception:

KeyError                                  Traceback (most recent call last)

/usr/local/lib/python3.10/dist-packages/pandas/core/indexes/base.py in get_loc(self, key, method, tolerance)
   3802                 return self._engine.get_loc(casted_key)
   3803             except KeyError as err:
-> 3804                 raise KeyError(key) from err
   3805             except TypeError:
   3806                 # If we have a listlike key, _check_indexing_error will raise

KeyError: 'parameter'