有没有一种很好的pythonic方法来过滤具有多个条件的数据帧？

Question

寻找一种进行多条件过滤的有效方法（最好不要遍历每一行）。

原始数据：

fruit      price  qty   comment
apple       1.5   10    In Stock
apple       0.7   20    In Stock
pear        3.0   5     In Stock
pear        2.0   5     In Stock 
pear        1.2   30    Out Stock

文件逻辑：

if fruit = 'apple'  keep price = 1.5
if fruit = 'Pear'   keep qty = 5

预期输出：

fruit      price  qty   comment
apple       1.5   10    In Stock
pear        3.0   5     In Stock
pear        2.0   5     In Stock

Answer 1

您需要使用&创建布尔型掩码，然后需要'|' 用于两个面罩合并。

m1 = ((df['fruit']=='apple') & (df['price']==1.5))
m2 = ((df['fruit']=='pear') & (df['qty']==5))
df.loc[m1 | m2]

输出：

   fruit    price   qty comment
0   apple   1.5 10  In Stock
2   pear    3.0 5   In Stock
3   pear    2.0 5   In Stock