【问题标题】：How to count frequency of a value in a column of a data frame based on another column?How to count frequency of a value in a column of a data frame based on another column?
【发布时间】：2022-12-02 03:10:59
【问题描述】：
I have dataframe with different traffic signs in different neighborhoods (both are columns). I want to count the quantity of each sign type in each neighborhood.
i could create a query for each neighborhood and the count the value of each sign type like that but there are too many neighborhoods for that to be practical.
【问题讨论】：
标签：
python
pandas
dataframe
【解决方案1】：
You can group by the neighbourhood and sign type and do a size to have the count of each sign type in each neighbourhood.
Sample code
df.groupby(["neighbourhood", "sign_type"]).size()