r-数据帧中的非数值相似变量

在下面的代码中，我选择DR等于零的列。

r <- data.frame(DR01 = 3, DR02 = 4, DR03 = 0, DR04 = 0) 

names(rev(r)[, cumsum(rev(r)) == 0])

[1] "DR04" "DR03

然而，我有一个包含更多信息的新数据库，但当我这样做时：names(rev(r)[, cumsum(rev(r)) == 0])给出一个错误：

Error in Math.data.frame(rev(r)) : 
  non-numeric-alike variable(s) in data frame: Week, Code, date2, date1

那么如何调整代码来修复这个错误呢？我相信我只需要选择DR我说得对吗？

新数据库

r <- structure(
  list(date1= c("2021-06-28","2021-06-28","2021-06-28","2021-06-28","2021-06-28",
                "2021-06-28","2021-06-28","2021-06-28"),
       date2 = c("2021-06-30","2021-06-30","2021-07-02","2021-07-07","2021-07-07","2021-07-09","2021-07-09","2021-07-09"),
       Code = c("FDE","ABC","ABC","ABC","CDE","FGE","ABC","CDE"),
       Week= c("Wednesday","Wednesday","Friday","Wednesday","Wednesday","Friday","Friday","Friday"),
       DR1 = c(4,1,4,3,3,4,3,5),
       DR01 = c(4,1,4,3,3,4,3,6), DR02= c(4,2,6,7,3,2,7,4),DR03= c(9,5,4,3,3,2,1,5),
       DR04 = c(5,4,3,3,6,2,1,9),DR05 = c(5,4,5,3,6,2,1,9),
       DR06 = c(2,4,3,3,5,6,7,8),DR07 = c(2,5,4,4,9,4,7,8),
       DR08 = c(0,0,0,1,2,0,0,0),DR09 = c(0,0,0,0,0,0,0,0),DR010 = c(0,0,0,0,0,0,0,0),DR011 = c(4,0,0,0,0,0,0,0), 
       DR012 = c(0,0,0,3,0,0,0,5),DR013 = c(0,0,1,0,0,0,2,0),DR014 = c(0,0,0,0,0,2,0,0)),
  class = "data.frame", row.names = c(NA, -8L))