sounds to me like you're hung up on how to keep pairs of values together. When you have a list.

There're a dozen ways to think of this issue.

One might ask why you have to pair them up at all. If you know the index in the array of the value you're interested in... then the next index is the pair. It's in the list already, why take it appart into pairs.

or if you needed to pull it apart into pairs (or groups of any arbitrary size (let's say instead of pairs, you had to group them into groups of five numbers at a time), which in some languages is done with multidimensional arrays, or you could create tuples--your own custom data type, using lists of lists, or be clever and concatentate the pairs together using an identifier (like you did with the space), or painstakingly keep track of two lists where you once had one...

The sky's the limit, each choice will have consequences, but you have to make a choice and try something out.