unable to use groupby function in pandas for dataframe

Question

I have a dataframe with 100+ rows, where i need to extract values w.r.t 'High' column using groupby. But I am unable to do it.

My dataframe sample is:

           Date     Open     High  ...    Volume              
           Date     Open     High  ...    Volume 
0    24-04-2020  1840.10  1851.60  ...     93384      
1    23-04-2020  1786.00  1891.70  ...    453645     
2    22-04-2020  1746.00  1789.10  ...    103696      
3    21-04-2020  1775.00  1794.00  ...    149222

I have stored the dataframe in a variable data_frame and when I try using data_frame.groupby('High') , I am getting the following error message:

"ValueError: Grouper for 'High' not 1-dimensional".

Any idea how I can fix this?

Answer 1

I think the problem is with the header, the header has multi-index and so specifying only one column name gives you error. You can set the column headers using the df.columns . If you want to access the High column, then simple use loc or `data_frame['High']

data_frame.columns = ['Date', 'Open', 'High', 'Volume'] #add more 

If you want to get the max value of the High column based on the date, then you have to use groupby on Date and project the High column.

data_frame.groupby(['Date'])['High'].max()