按描述计数 pandas DataFrame 条目

Question

I have a dataset ( DataFrame ) with transactions and a description for every transaction. Additional every transaction has a value.

How can count the number of transactions per description and how can I sum up all values for one description.

I am sure, this was asked before, but I am not sure what I am looking for... So just point me to the function names.

Answer 1

You could use groupby.count()

DataFrame.groupby(['description']).count()

Answer 2

Let's use groupby and agg with 'size' and 'sum'. Look at pandas split-apply-combine :

import pandas as pd
from seaborn import load_dataset

tips = load_dataset('tips')
df_out = tips.groupby('time')['total_bill'].agg(['size', 'sum'])
df_out

Output:

        size      sum
time                 
Lunch     68  1167.47
Dinner   176  3660.30