我有一个数据框:
df<-data.frame(P = c("A","A","A", "B","B","B", "C", "C", "C"),
index = c("ind1","ind2","ind3","ind1","ind2","ind3","ind1","ind2","ind3"),
var = c(2,1,1,8,5,4,2,8,6))
我想要获得每个P
值的所有var
的最小值及其相关的index
。
我可以这样做:
DT <- data.table(df)
DT[ ,.SD[which.min(var)], by = P]
通过 P
,只会给出一个 var
的最小值(第一个):
抱歉,我只能用英文进行交流和回答问题。P index var 1: A ind2 1 2: B ind3 4 3: C ind1 2
有什么想法吗?P index var 1: A ind2 1 2: A ind3 1 2: B ind3 4 3: C ind1 2