Here is my sample dataframe:
df = pd.DataFrame(data=[[3, np.nan, np.nan],[5, np.nan, np.nan]], index=['country1', 'country2'], columns=[2021, 2022, 2023])
Here is my sample dictionary:
d = {'country1': {'key1': 'a', 'key2': 'assumed','key3': {2022: '10', 2023: ' 20'}}, 'country2': {'key1': 'b', 'key2': 'assumed', 'key3': {2022: '30', 2023: ' 40'}}}
I am aiming to use the dictionary d to replace the missing values in the dataframe df. I thought I'd use something like:
df.fillna(d2)
where d2 is a dictionary based on dictionary d:
d2 = {'country1': {2022: '10', 2023: ' 20'}, 'country2': {2022: '30', 2023: ' 40'}}
I don't know how to generate d2 but it doesn't work anyway.
The result would look like this:
pd.DataFrame(data=[[3, 10, 20],[5, 30, 40]], index=['country1', 'country2'], columns=[2021, 2022, 2023])
We can still use fillna but before that we have to normalize/transform the dictionary in a format which is suitable for fillna
df.T.fillna({k: v['key3'] for k, v in d.items()}).T
Result
2021 2022 2023
country1 3.0 10 20
country2 5.0 30 40