为每个ID删除低值行

Question

我有一个包含三个变量的数据，并且我希望保留具有高“值”的id行，并为每个id删除具有低“值”的行。

我有什么

mydata <- data.frame(id=c(1,1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,4), case=c("a","b","c","c","b","a","b","c","c","a","b","c","c","a","b","c","a","b"), value=c(1,1,1,2,2,1,1,2,2,2,2,1,1,1,1,1,2,2)) 

我需要什么

id case value 
4 1 c 2 
5 1 b 2 
8 2 c 2 
9 2 c 2 
10 3 a 2 
11 3 b 2 
17 4 a 2 
18 4 b 2 

谢谢！

Answer 1

尝试：

mydata[mydata$value==ave(mydata$value,mydata$id,FUN=max),] 

Answer 2

mydata[mydata$value>1,] 

或

mydata[mydata$value>min(mydata$value),]