Pandas- 根据条件从 DataFrame 中选择行

Question

数据帧 :

category  value   
A         25  
B         10  
A         15  
B         28  
A         18

需要选择满足以下条件的行，
1. category=A和 10 到 20 之间的值
2. A以外的类别

Answer 1

我想你需要 boolean indexing :

df1 = df[(df['category'] == 'A') & (df['value'].between(10,20))]
print (df1)
  category  value
2        A     15
4        A     18

进而:

df2 = df[(df['category'] != 'A') & (df['value'].between(10,20))]
print (df2)
  category  value
1        B     10

或者:

df3 = df[df['category'] != 'A']
print (df3)
  category  value
1        B     10
3        B     28

编辑:用 | 加入这两个条件为 or ，别忘了加 ()到第一个条件。

df1 = df[((df['category'] == 'A') & (df['value'].between(10,20))) | 
         (df['category'] != 'A')]
print (df1)
  category  value
1        B     10
2        A     15
3        B     28
4        A     18