Google Spreadsheet: Use column + n in formular - google-sheets

Question

In my spreadsheet in Column X I have the following formular:
=ImportRange('_keys'!$B$2;"2015!A200:A203")
Now I'd like to copy this formular to column X+n (in this case X+2) so that it should look like:
=ImportRange('_keys'!$B$2;"2015!C200:C203")
But it doesn't change the column and I have to change it by hand.
Is it possible to change this formular that it always uses the column where the formular is in?

Answer 1

You can use the COLUMN() function to get the column of the current cell as a number. Using ADDRESS() you can turn it into a cell reference string. See the docs for COLUMN and ADDRESS.
Your code becomes
=ImportRange('_keys'!$B$2;
CONCATENATE("2015!", ADDRESS(200, COLUMN()-Y, 4),
":", ADDRESS(203, COLUMN()-Y, 4))
)
where Y is the offset between column A and column X (where this formula is located). The third argument of ADDRESS makes both the row and column relative (without the $). Note that the order of arguments to ADDRESS is row then column, annoyingly.

Answer 2

My solution:
I wrote a simple custom function that converts numbers into letters.
/**
* Converts number of column into column letter
*
* #param {Number} aNumer Number of column
* #return {String} Letter of column
* #customfunction
*/
function COL_NR2LETTER(aNumber) {
var letterArray = ['-', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'AA', 'AB', 'AC', 'AD', 'AE', 'AF', 'AG', 'AH', 'AI', 'AJ', 'AK', 'AL', 'AM', 'AN', 'AO', 'AP', 'AQ', 'AR', 'AS', 'AT', 'AU', 'AV', 'AW', 'AX', 'AY', 'AZ'];
if (aNumber < 1 || aNumber > letterArray.length)
throw "column index out of bound error";
return letterArray [aNumber];
}
Now its possible to copy
=ImportRange('_keys'!$B$2;
"2015!" & COL_NR2LETTER(Column(A1)) &"200:"& COL_NR2LETTER(Column(A1)) &"203")
from Column X into a column X+n.