r - Subset elements in a list based on a logical condition

Question

How can I subset a list based on a condition (TRUE, FALSE) in another list? Please, see my example below:

l <- list(a=c(1,2,3), b=c(4,5,6,5), c=c(3,4,5,6))
l
$a
[1] 1 2 3

$b
[1] 4 5 6 5

$c
[1] 3 4 5 6

cond <- lapply(l, function(x) length(x) > 3)
cond
$a
[1] FALSE

$b
[1] TRUE

$c
[1] TRUE

> l[cond]

Error in l[cond] : invalid subscript type 'list'

Answer 1

This is what the Filter function was made for:

Filter(function(x) length(x) > 3, l)
$b
[1] 4 5 6 5

$c
[1] 3 4 5 6