How do I find which list has n numbers of values greater than x in R?

Question

I have a list containing multiple members ( list1 ). Each member in the list contains various numbers. I want to find the list member(s) that have at least 3 values greater than or equal to 5. How can I accomplish this?

aa <- c(1,2,3,4,5)
bb <- c(5,6,9,7,8)
cc <- c(3,8,5,1,6)

list1 <- list(aa,bb,cc)

In this case, I'd like to see bb and cc be returned. Thanks!

Answer 1

You can use Filter to return a filtered object

Filter(function(x) sum(x>=5)>=3,list1)

Or if you want a "hadley" solution

devtools::install_github("hadley/purrr")
list1 %>% keep(function(x) sum(x>=5)>=3)

Answer 2

if you just want the index of the elements that satisfy your condition, use:

which(sapply(list1,function(x)sum(x>=5))>=3)

if you want the names of the list elements that match your condition, use:

names(list1)[sapply(list1,function(x)sum(x>=5))>=3]