汇总Pandas数据帧中的部分列

Question

Let's say I have two columns in my Pandas dataframe

Category   Price
Weekend       30
Weekend       20
Thursday      10
Wednesday      5
Weekend       55

I want to summarize the categories and add the values. I want to add all values of "Weekend" together and store it in a dictionary for example. So I have something like:

summary = {"Weekend":105, "Thursday": 10, "Wednesday": 5}

How can I easily do this?

Answer 1

You could use .groupby() and then .sum() .

>>> df = pd.DataFrame(dict(Category=['Weekend', 'Weekend', 
                                     'Thursday', 'Wednesday', 'Weekend'], 
                           Price=[30, 20, 10, 5, 55]))

>>> df.groupby('Category').sum()
           Price
Category        
Thursday      10
Wednesday      5
Weekend      105

>>> df.groupby('Category').sum().Price.to_dict()
{'Thursday': 10, 'Wednesday': 5, 'Weekend': 105}