How do I Loop through an Array and Create a New String from The Array Values?

Hello Gaskin Design Studios (My user name might say RinesJoseph I'm the same GUY XD ) here and once again I am asking the community for help with a simple problem.

I am trying to create a function that will loop through an array, take the values from that array and build a string from them.

So far I got this below

I'm figure out the right expression that will build the string.

(TruSize the number of non(-1) values in the array. I want the loop to go from 0 to that value in the array building the string as it goes.)

I need to be able to do this without hardcoding because I could have a random number of values in the array.

If you can please help me with any suggestions I'll owe you a favor ;) Thank you Construct 2 community you never let me down yet!!!

and I'm using Construct 2 not 3 hopefully it doesnt make too much of a difference