I have a data frame df and I use several columns from it to groupby:
In the above way, I almost get the table (data frame) that I need. What is missing is an additional column that contains a number of rows in each group. In other words, I have mean but I also would like to know how many numbers were used to get these means. For example, in the first group there are 8 values and in the second one 10 and so on.
In short: How do I get group-wise statistics for a dataframe?