‘key of type tuple not found and not a multiindex’

Query: ‘key of type tuple not found and not a multiindex’

This error typically occurs when you are trying to access a key in a pandas DataFrame or Series using a tuple as the key, but that key is not found in the DataFrame or Series. Additionally, this error also arises when you are trying to access a key that should be part of a MultiIndex, but the key is not a MultiIndex.

Example 1:

    import pandas as pd

    # Create a DataFrame
    data = {'A': [1, 2, 3],
            'B': [4, 5, 6]}
    df = pd.DataFrame(data)

    # Trying to access a non-existent key with a tuple
    key = ('C', 'D')
    value = df[key]
    # Raises KeyError: ('C', 'D') not found in axis
  

In this example, we create a DataFrame with columns ‘A’ and ‘B’. We then try to access a non-existent key using a tuple (‘C’, ‘D’). Since this key is not found in the DataFrame, a KeyError is raised.

Example 2:

    import pandas as pd

    # Create a DataFrame
    data = {'A': [1, 2, 3],
            'B': [4, 5, 6]}
    index = pd.MultiIndex.from_tuples([('X', 'a'), ('X', 'b'), ('Y', 'a')], names=['Key1', 'Key2'])
    df = pd.DataFrame(data, index=index)

    # Trying to access a key with a wrong format
    key = ('Z', 'a')
    value = df[key]
    # Raises KeyError: ('Z', 'a') not found in axis
  

In this example, we create a DataFrame with MultiIndex using two levels of keys: ‘Key1’ and ‘Key2’. We then try to access a key (‘Z’, ‘a’), which does not exist in the MultiIndex. Therefore, a KeyError is raised.

To resolve this error, ensure that you are using the correct keys when accessing data in a pandas DataFrame or Series. Double-check the formatting of your keys and verify that they exist in the DataFrame or Series you are working with. If you are working with a MultiIndex, make sure that the key you are trying to access matches the format of the MultiIndex.