How to filter (with dplyr) for all values of a group if variable limit is reached?

Question

Here\'s the dummy data:

cases <- rep(1:5,times=2)
var1 <- as.numeric(c(450,100,250,999,200,500,980,10,700,1000))
var2 <- as.numeric(c(111,222,333,4         


        

Answer 1

Filter by max(var1) in each group defined by cases:

maindata1 %>%
  group_by(cases) %>%
  filter(max(var1) > 950) %>%
  arrange(cases)

#   cases var1 var2
# 1     2  100  222
# 2     2  980  915
# 3     4  999  444
# 4     4  700  105
# 5     5  200  424
# 6     5 1000  152