Question

我想生成一种药物的结束日期，其中将结束日期定义为未注册该药物的第一个日期。我有以下三种药物，a，b，c以及处方药可以注册的日期

Drug <- c("a","b","a","b","c","a","c","a","c","c")

Date <- c("2018-09-20","2018-09-20" , "2018-09-21","2018-09-21","2018-09-21",
     "2018-09-22" ,"2018-09-22" ,"2018-09-23","2018-09-23",
     "2018-09-24")
Dates <- cbind(Drug,Date)


     Drug    Date         
[1,] "a"  "2018-09-20"
[2,] "b"  "2018-09-20"
[3,] "a"  "2018-09-21"
[4,] "b"  "2018-09-21"
[5,] "c"  "2018-09-21"
[6,] "a"  "2018-09-22"
[7,] "c"  "2018-09-22"
[8,] "a"  "2018-09-23"
[9,] "c"  "2018-09-23"
[10,] "c"  "2018-09-24"

我希望我的决赛桌看起来像这样：

end <- c("2018-09-24","2018-09-22" ,"2018-09-24","2018-09-22" ,NA,"2018-09-24",
          NA,"2018-09-24",NA,NA)

Dates <- cbind(Dates,end)


Drug      res          end         
 "a"  "2018-09-20"  "2018-09-24"
 "b"  "2018-09-20"  "2018-09-22"
 "a"  "2018-09-21"  "2018-09-24"
 "b"  "2018-09-21"  "2018-09-22"
 "c"  "2018-09-21"  NA          
 "a"  "2018-09-22"  "2018-09-24"
 "c"  "2018-09-22"  NA          
 "a"  "2018-09-23"  "2018-09-24"
 "c"  "2018-09-23"  NA          
 "c" "2018-09-24"   NA

Answer 1

首先，我将您的数据集转换为数据框，以使多种操作变得更加容易。我将创建一个“帮助程序”数据框来存储每种药物的唯一终止日期，然后将这些日期添加到原始数据集中。

一路走来，我还将创建一个实用工具功能，该功能可以找到给定日期之后的日期。（根据所需解决方案中NA的出现，我假设当您说“未注册药物的第一个日期”时，您指的是日期列表中的第一个日期，而不仅仅是下一个日历日。）

library(dplyr)

Dates = as.data.frame(Dates, stringsAsFactors = FALSE)

next_date <- function(one_date, all_dates) {
    all_dates <- sort(unique(all_dates))
    return(all_dates[which(one_date == all_dates)[[1]] + 1])
}

end_dates <- group_by(Dates, Drug)
end_dates <- summarize(end_dates, end = next_date(max(Date), Dates$Date))

Dates = left_join(Dates, end_dates)

选择数据框中的下一个不同日期

1 个答案: