在 pandas 分组之后对每个组进行采样

本文介绍了在 pandas 分组之后对每个组进行采样的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我知道必须在某些地方回答此问题，但我只是找不到它.

I know this must have been answered some where but I just could not find it.

问题:对分组进行分组操作后进行采样.

Problem: Sample each group after groupby operation.

import pandas as pd df = pd.DataFrame({'a': [1,2,3,4,5,6,7], 'b': [1,1,1,0,0,0,0]}) grouped = df.groupby('b') # now sample from each group, e.g., I want 30% of each group

推荐答案

应用lambda并调用 sample ，参数为frac:

Apply a lambda and call sample with param frac:

In [2]: df = pd.DataFrame({'a': [1,2,3,4,5,6,7], 'b': [1,1,1,0,0,0,0]}) ​ grouped = df.groupby('b') grouped.apply(lambda x: x.sample(frac=0.3)) Out[2]: a b b 0 6 7 0 1 2 3 1