Can you have the array returned as a simple comma delimited string like 5,6,7?

I don't think so. If that is possible, it's beyond my abilities. The formula in A1 is an array formula that returns an array. Specifically, it's ={MATCH((B1:F1),RowOfHeaders,0)}. It returns an array (like {0,2,34,1,0}).

I had thought that maybe, if I could somehow convert the answer array (in A1) into a text string, then I could refer to A1 with Indirect with my formula in another cell.

Or maybe I'm going about this the wrong way? I have a very large workbook with long formulas that I am optimizing. Many of the formulas have the section "MATCH((B5:F5),RowOfHeaders,0)" repeating, and the answer array doesn't change when it's copied down (is always calculated to be {0,2,34,1,0} with the given input data). I thought that if I could move that section out to a single cell, and just refer to that cell in other formulas, I could significantly speed up my formulas.

For a simplified example (let's say it's in A5) is something like:

={sum(INDEX(Table1,MATCH((B1:F1),RowOfHeaders,0),1)+vlookup("Key2",Table2,MATCH((B1:F1),RowOfHeaders,0))*(MATCH((B1:F1),RowOfHeaders,0)*12))}

That formula is copied down.

So if I could replace my formula with something like:

={sum(INDEX(Table1,indirect($A$1),1)+vlookup("Key2",Table2,indirect($A$1))*(indirect($A$1)*12))}

My workbook should run much faster. In my workbook, the actual formula is much longer and copied down for many rows. But it's slowing down.

So I either would like to:

a) Refer to an array in a cell (generated by an array formula) used by an array formula in another cell, OR

b) Figure out some other way to make my array formulas more efficient by reducing repeating sections that output the same array (with given input data).