Duplicate list names in R
When you have duplicate names and you call a subset by name, only the first element is returned. In fact, [[ will only ever give you one element anyway, so let's look at [ instead.
l["B"]# $B# [1] 5We can also see that trying c("B", "B") as the subset won't even give us the right result because R goes back and gets the first B again.
l[c("B", "B")]# $B# [1] 5## $B# [1] 5One of the safest ways to retrieve all the B elements is to use a logical subset of the names() vector. This will give us the correct elements.
l[names(l) == "B"]# $B# [1] 5## $B# [1] 7This is a great example of why duplicate names should be avoided.