title: How to get the number of columns of worksheet as integer (28) instead of Excel-letters ("AB")?
body: <p>Given:</p>
  
  <pre><code>$this-&gt;objPHPExcelReader = PHPExcel_IOFactory::createReaderForFile($this-&gt;config['file']);
  $this-&gt;objPHPExcelReader-&gt;setLoadSheetsOnly(array($this-&gt;config['worksheet']));
  $this-&gt;objPHPExcelReader-&gt;setReadDataOnly(true);
  $this-&gt;objPHPExcel = $this-&gt;objPHPExcelReader-&gt;load($this-&gt;config['file']);
  </code></pre>
  
  <p>I can iterate through the rows like this but it is <strong>very slow</strong>, i.e. in a 3MB Excel file with a worksheet that has <strong>"EL" columns</strong>, it takes about <strong>1 second per row</strong>:</p>
  
  <pre><code>foreach ($this-&gt;objPHPExcel-&gt;setActiveSheetIndex(0)-&gt;getRowIterator() as $row)
  {
      $dataset = array();
      $cellIterator = $row-&gt;getCellIterator();
      $cellIterator-&gt;setIterateOnlyExistingCells(false);
      foreach ($cellIterator as $cell)
      {
          if (!is_null($cell))
          {
              $dataset[] = $cell-&gt;getCalculatedValue();
          }
      }
      $this-&gt;datasets[] = $dataset;
  }
  </code></pre>
  
  <p>When I iterate like this, it it significantly faster (approx. 2000 rows in 30 seconds), but I will have to convert the letters e.g. "EL" to a number:</p>
  
  <pre><code>$highestColumm = $this-&gt;objPHPExcel-&gt;setActiveSheetIndex(0)-&gt;getHighestColumn(); // e.g. "EL"
  $highestRow = $this-&gt;objPHPExcel-&gt;setActiveSheetIndex(0)-&gt;getHighestRow();
  
  $number_of_columns = 150; // TODO: figure out how to get the number of cols as int
  for ($row = 1; $row &lt; $highestRow + 1; $row++) {
      $dataset = array();
      for ($column = 0; $column &lt; $number_of_columns; $column++) {
          $dataset[] = $this-&gt;objPHPExcel-&gt;setActiveSheetIndex(0)-&gt;getCellByColumnAndRow($column, $row)-&gt;getValue();
      }
      $this-&gt;datasets[] = $dataset;
  }
  </code></pre>
  
  <p><strong>Is there a way to get the highest column as an integer (e.g. "28") instead of in Excel-styled letters (e.g. "AB")?</strong></p>