我有一个df,如下所示.我想找到date
年之前发生的最近的日期(from R_1:R_10)
.这是一种一次计算R1:R10
到date
天的差值,然后 Select 我们想要的值,然后将其放入新变量cdate
的方法吗?
输出如下所示:
cdate
将由R\u 1:R10日期标识,以负值最大的日期为输入cdate
的日期
示例数据:
df<-structure(list(id = c("A0003", "A0003", "A0003", "A0003", "A0003",
"A0003", "A0005", "A0005"), date = structure(c(17774, 17799,
17805, 17837, 17846, 17873, 17784, 17784), class = "Date"), R_1 = structure(c(17773,
17773, 17773, 17773, 17773, 17773, 17785, 17785), class = "Date"),
R_2 = structure(c(17815, 17815, 17815, 17815, 17815, 17815,
17827, 17827), class = "Date"), R_5 = structure(c(17794,
17794, 17794, 17794, 17794, 17794, 17806, 17806), class = "Date"),
R_10 = structure(c(17871, 17871, 17871, 17871, 17871, 17871,
NA, NA), class = "Date")), row.names = c(NA, 8L), class = "data.frame")