从熊猫数据框中删除特定的行

使用value_counts()上studentID

import pandas as pd

df = pd.DataFrame({'studentID':['a','a','a','b','b','b', 'c'],
                   'problemID':[1,2,3,1,2,3,1]})
print(df)
tmp = df['studentID'].value_counts()
tmp = tmp[tmp >= 3]
new_df = df[df['studentID'].isin(tmp.index)]
print(new_df)

输出：

  studentID  problemID
0         a          1
1         a          2
2         a          3
3         b          1
4         b          2
5         b          3
6         c          1

  studentID  problemID
0         a          1
1         a          2
2         a          3
3         b          1
4         b          2
5         b          3