How to to calculate each decile average based on group?

Hi guys,

I have a table with variables 'Date', 'Volumn'. Now I want to first group the variable by 'Date', then under each group, I want to calculate the average of first decile of 'Volumn'. Finally I want to generage a new table associates 'Date' and the calculated 'Average First Decile Volumn'. Is there any easy way to do this?

Thanks a lot.

Answer 1

[Jalaj Gambhir]

Hi,

In a table, you can first group rows using unique date values in the Date column, then compute your required statistics using accumarray. You can refer to the example below:

dates = T.Date;
[uniqueDates,ua,uc] = unique(dates);
mean_T = accumarray(uc,T.Volumn,[],@mean);
new_table = table(uniqueDates,mean_T);

You can replace @mean with your function to compute average first decile. Refer prctile for the same.