,我有以下的數據幀:查找最大日期爲每個ID
id<-c(1,1,2,3,3)
date<-c("23-01-08","01-11-07","30-11-07","17-12-07","12-12-08")
df<-data.frame(id,date)
df$date2<-as.Date(as.character(df$date), format = "%d-%m-%y")
id date date2
1 23-01-08 2008-01-23
1 01-11-07 2007-11-01
2 30-11-07 2007-11-30
3 17-12-07 2007-12-17
3 12-12-08 2008-12-12
現在我需要創建一個第四列並插入,每個id
交易的最大日期。 最終的表應該是如下:
id date date2 max
1 23-01-08 2008-01-23 2008-01-23
1 01-11-07 2007-11-01 0
2 30-11-07 2007-11-30 2007-11-30
3 17-12-07 2007-12-17 0
3 12-12-08 2008-12-12 2008-12-12
我會感激,如果你能幫助我。
我以這種方式使用它:mutate(flag_last = if_else(date == max(date),TRUE,FALSE))%>%filter(flag_last == TRUE) – Rohit