(solved) Filter out blank characters of a list?

Hey Guys, could anyone have a quick answer on how to filter out blank characters of a list?

I'm trying to set the send messages inside a poly with the poly instances numer (prepend echo -> echo 1, echo 2, echo 3) but the receive tilda object only works when it's (echo1, echo2, echo3 etc)

Anyone has an idea?

Thanks Imbie

Edit: Found the solution with the combine object