Get relative column numbers in range

The first COLUMN function generates an array of 7 numbers like this:

{2,3,4,5,6,7,8}

The second COLUMN function generates an array with just one item like this:

{2}

which is then subtracted from the first array to yield:

{0,1,2,3,4,5,6}

Finally, 1 is added to get:

{1,2,3,4,5,6,7}

With a named range

You can adapt this formula to use with a named range. For example, in the above example, if you created a named range "data" for B4:H4, you can use this formula to generate column numbers:

{=COLUMN(data)-COLUMN(INDEX(data,1,1))+1}

In other array formulas

You'll encounter this formula in other array formulas that need to process data column-by-column.