摘要: library(data.table)ID <- c(NA,1,2,2)IDTime <- c(1,2,NA,1)TimeX1 <- c(5,3,NA,2)X1X2 <- c(NA,5,1,4)X2mydata <- data.table(ID,Time,X1,X2) mydata ```````` 阅读全文
posted @ 2016-12-19 13:57 qinqinyang 阅读(2731) 评论(0) 推荐(0)