摘要: require(reshape2)x = data.frame(subject = c("John", "Mary"), time = c(1,1), age = c(33,NA), weight = c(90, NA), height = c(2,2))x subject time age wei阅读全文
posted @ 2018-05-08 04:59 emanlee 阅读(35) 评论(0) 编辑