给定类的分布和这些类的示例行的数据帧,是否有一种简单/快速的方法从数据帧中采样与给定分布匹配的分布,其中没有足够示例的类会减少其他类中的示例数:
例如
+------+-------+-------+
| col1 | col2 | class |
+------+-------+-------+
| 4 | 45 | A |
+------+-------+-------+
| 5 | 66 | B |
+------+-------+-------+
| 5 | 6 | C |
+------+-------+-------+
| 4 | 6 | A |
+------+-------+-------+
| 321 | 1 | A |
+------+-------+-------+
| 32 | 432 | A |
+------+-------+-------+
| 5 | 3 | B |
+------+-------+-------+
given a dataframe like above and the distribution like below:
+-------+--------------+
| class | proportion |
+-------+--------------+
| A | 0.50 |
+-------+--------------+
| B | 0.25 |
+-------+--------------+
| C | 0.25 |
+-------+--------------+
I would like to return something like:
+------+-------+-------+
| col1 | col2 | class |
+------+-------+-------+
| 5 | 66 | B |
+------+-------+-------+
| 5 | 6 | C |
+------+-------+-------+
| 4 | 6 | A |
+------+-------+-------+
| 32 | 432 | A |
+------+-------+-------+
df.sample
支持称重实体:
s = pd.Series({'A': 0.5, 'B': 0.25, 'C': 0.25})
df.sample(n, weights=df['class'].map(s/df['class'].value_counts()))
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