熊猫如何在python熊猫中实现此SQL语法

Question

SQL： 选择类型，计数（当y = 2然后1结束的情况） 从表 按类型分组

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结果是 enter image description here

感谢帮助！

Answer 1

import pandas as pd
import numpy as np
table1 = pd.DataFrame({'type': ['a','b','b','c','c','b','a','a','a','a','b','b','c','c','c','c',
                               'c','c','c'],
                        'y':[2,2,0,0,2,0,2,2,2,2,2,2,2,0,0,0,0,0,0],

                      })
table1_2_count=table1.loc[(table1['y'] == 2) , :]
table1_2_count.groupby('type')['y'].count()

Answer 2

您需要pd.Series.value_counts

table1[table1['y'].eq(2)]['type'].value_counts()
[out]
a    5
b    3
c    2
Name: type, dtype: int64