title: Convert numbers to Excel Column Letters in Power Query
body: <p>I would like to transform Numbers to Excel Column Letters.</p>
  <p>There are several threads on the topic but it seems that it has not been answered yet for M language.</p>
  <p>I managed to address it with the following code but I am sure someone will have a much more efficient code to propose:</p>
  <pre><code>= Table.AddColumn(Source, &quot;Column Letter&quot;, each Text.Combine({ if (Number.IntegerDivide(
      Number.IntegerDivide(
          Number.IntegerDivide([Column1]-1,1),26)-1,26))&lt;1 then &quot;&quot; else Character.FromNumber( 64+Number.IntegerDivide(Number.IntegerDivide(Number.IntegerDivide([Column1]-1,1),26)-1,26)),
  (if Number.IntegerDivide([Column1]-1,26)-
  Number.Abs(
      Number.IntegerDivide(
          Number.IntegerDivide([Column1]-1,26)
          -1,26)*26)&lt;1 then &quot;&quot; else 
          Character.FromNumber(64+
          Number.IntegerDivide([Column1]-1,26)-Number.Abs(
              Number.IntegerDivide(
                  Number.IntegerDivide([Column1]-1,26)-1,26)*26))),
      (if [Column1]-Number.Abs(
      Number.IntegerDivide([Column1]-1,26)*26)&lt;1 then &quot;&quot; else Character.FromNumber(64+[Column1]-Number.Abs(
      Number.IntegerDivide([Column1]-1,26)*26)))})) 
  </code></pre>
  <p>Thank you!</p>