我正在尝试计算cumsum从每一组的最后一行到第一行的起点.
样本数据:
t1 <- data.frame(var = "a", val = c(0,0,0,0,1,0,0,0,0,1,0,0,0,0,0))
t2 <- data.frame(var = "b", val = c(0,0,0,0,1,0,0,1,0,0,0,0,0,0,0))
ts <- rbind(t1, t2)
所需格式(按分组var):
ts <- data.frame(var = c("a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a",
"b", "b", "b", "b", "b", "b", "b", "b", "b", "b", "b", "b", "b", "b", "b"),
val = c(2,2,2,2,2,1,1,1,1,1,0,0,0,0,0,2,2,2,2,2,1,1,1,0,0,0,0,0,0,0))