pandas Groupby AGG-如何获得计数？ [英] Pandas groupby agg - how to get counts?

问题描述

我正在尝试获取指标的总和，均值和计数

I am trying to get sum, mean and count of a metric

df.groupby(['id', 'pushid']).agg({"sess_length": [ np.sum, np.mean, np.count]})

但是我得到模块'numpy'没有属性'count'，我尝试了多种表达count函数的方法，但无法使其正常工作。我如何只将一个记录总数与其他指标一起计算？

But I get "module 'numpy' has no attribute 'count'", and I have tried different ways of expressing the count function but can't get it to work. How do I just an aggregate record count together with the other metrics?

推荐答案

您可以使用字符串代替函数，就像这样：

You can use strings instead of the functions, like so:

In [16]: df = pd.DataFrame({"id": list("ccdef"), 
                            "pushid": list("aabbc"),
                            "sess_length": [10, 20, 30, 40, 50]})

In [17]: df.groupby(['id', 'pushid']).agg({"sess_length": [ 'sum', 'mean', 'count']})

Out[17]:           sess_length
                           sum mean count
         id pushid
         c  a               30   15     2
         d  b               30   30     1
         e  b               40   40     1
         f  c               50   50     1

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