我有一个包含三列的数据帧:GROUP、AMPLATION ORIGIN.我想删除相同组内的重复值.我找不到一种方法来对unique()进行分组，也想不出一种方法来应用case_when().我有许多组值，所以虽然我可以想象如何 for each 组硬编码和if语句，但我想有一种更好的方法来做到这一点.

谢谢!

df <- data.frame(
  Group = c(rep("A",4), rep("B",3), rep("A",2), rep("B",4)),
  Amplitude = c(2,3,5,7,2,4,6,2,4,2,4,6,9),
  Origin = c(rep("Drug", 7), rep("Placebo", 6))
  )

desired_df <- data.frame(
  Group = c(rep("A",5), rep("B",4)),
  Amplitude = c(2,3,4,5,7,2,4,6,9)
  )

>df
| Group | Amplitude | Origin  |
|-------|-----------|---------|
| A     | 2         | Drug    |
| A     | 3         | Drug    |
| A     | 5         | Drug    |
| A     | 7         | Drug    |
| B     | 2         | Drug    |
| B     | 4         | Drug    |
| B     | 6         | Drug    |
| A     | 2         | Placebo |
| A     | 4         | Placebo |
| B     | 2         | Placebo |
| B     | 4         | Placebo |
| B     | 6         | Placebo |
| B     | 9         | Placebo |


>desired_df
| Group | Amplitude |
|-------|-----------|
| A     | 2         |
| A     | 3         |
| A     | 4         |
| A     | 5         |
| A     | 7         |
| B     | 2         |
| B     | 4         |
| B     | 6         |
| B     | 9         |
…