CODEWITHSUNDEEP
r
Julien Navarre
Julien Navarre

Reputation: 7840

Access to element with the same names in a list

I have a list with elements that have the same name "element".

li <- list(element=list(id=1, name="x"), element=list(id=2, name="y"))

And I want to get the "name" of the element with an "id" equals to X.

Firstly i thought that I could do it with : 

 li[[which(li$element$id == 1)]]$name

But the problem is that li$element refers to the first element "element" of the list ...

> li$element
$id
[1] 1

$name
[1] "x"

So if I look for an id different from the id of the first element of my list it returns "interger(0)"

> which(li$element$id == 2)
integer(0)

Actually I do like this :

for (element in li) {
    if(element$id == 2) {
        name <- element$name
    }
}

But I wonder if there is a better way to do it, or if I missed something with the basic list notions (acces to elements ...).

Thank you

Upvotes: 0

Views: 642

Answers (1)

Roland
Roland

Reputation: 132989

li[sapply(li, function(x) x["id"]==2)][[1]][["name"]]
#[1] "y"

Upvotes: 1

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