add value only when true

hi I am making an array with the iteration values of for loop by chechking the conditions and i want it to be done only when my condition is true.

But now what is hapenning is that if the condition is false 0 is over wirrting my values.

And also i have put two for loops inside a for loop.

the second for loop is running to the first loop iterations.

thanks in advance

 I am adding the vi i have made .