.groupby .agg does not work as expected in python

Question

My dataframe is like:

I used the following code to calculate the sum, mean and std of a column for each group, but it gave me an error.

New11.groupby(level=0)['Population'].agg([np.sum,np.mean,np.std])
DataError: No numeric types to aggregate

However, the following code worked fine.

New11.groupby(level=0)['Population'].agg([np.sum])

This code gives an error.

New11.groupby(level=0)['Population'].agg([np.average])
AttributeError: 'float' object has no attribute 'dtype'

How should I modify my code to make it work?

Answer 1

Please try convert the values of 'Population' in float32 of the next form New11['Population]=np.float32(New11['Population']) . You can check this in the documentation

Answer 2

尝试

New11.groupby(level=0).agg({'Population': ['sum', 'mean', 'std']})