remove every other value in array

[caledonian_tartan]

hello
i'm a bit stuck here:

how can i remove every other value of an array? e.g. 1,2,3,4,5,6 -> 1,3,5

i tried with modulo, but the filter node does not work with arrays...

[caledonian_tartan]

seems like this works.

the "-1" gives me a correct array size. if put to 0 (or other legal ID) the array size does not change.

[nautilus]

so the value "-1" deletes an array entry?
(so time ago i heard smething similar with -2 or polygons when building topo).
is that true?

[NNois]

find in array then remove from array ?

[Mathaeus]

i'd try something like building a new array of half size, separately. Then, "get array indices", multiply by 2, select in original array. Should be faster than activating the "find in array", also somehow I feel more "safe" if new array is already defined, before.
Anyway whatever works, works...