例子：统计gender列不同性别的值分别的总个数

    df=pd.DataFrame({'gender':['male','famael','famael'],'result':['python','python','java']})
    print(df)
    print(df.groupby('gender').result.count())

结果：

   gender  result
0    male  python
1  famael  python
2  famael    java
gender
famael    2
male      1
Name: result, dtype: int64

Process finished with exit code 0