Convert column index into corresponding column letter

Question

I need to convert a Google Spreadsheet column index into its corresponding letter value, for example, given a spreadsheet:

I need to do this (this function obviously does not exist, it's an example):

getColumnLetterByIndex(4);  // this should return "D" getColumnLetterByIndex(1);  // this should return "A" getColumnLetterByIndex(6);  // this should return "F" 

Now, I don't recall exactly if the index starts from 0 or from 1, anyway the concept should be clear.

I didn't find anything about this on gas documentation.. am I blind? Any idea?

Thank you

Answer 1

I wrote these a while back for various purposes (will return the double-letter column names for column numbers > 26):

function columnToLetter(column) {   var temp, letter = '';   while (column > 0)   {     temp = (column - 1) % 26;     letter = String.fromCharCode(temp + 65) + letter;     column = (column - temp - 1) / 26;   }   return letter; }  function letterToColumn(letter) {   var column = 0, length = letter.length;   for (var i = 0; i < length; i++)   {     column += (letter.charCodeAt(i) - 64) * Math.pow(26, length - i - 1);   }   return column; } 

Answer 2

This works good

=REGEXEXTRACT(ADDRESS(ROW(); COLUMN()); "[A-Z]+") 

even for columns beyond Z.

Simply replace COLUMN() with your column number. The value of ROW() doesn't matter.