code: public static function COUNTIF($aArgs, $condition)
      {
          $returnValue = 0;
  
          $aArgs = Functions::flattenArray($aArgs);
          $condition = Functions::ifCondition($condition);
          // Loop through arguments
          foreach ($aArgs as $arg) {
              if (!is_numeric($arg)) {
                  $arg = Calculation::wrapResult(strtoupper($arg));
              }
              $testCondition = '=' . $arg . $condition;
              if (Calculation::getInstance()->_calculateFormulaValue($testCondition)) {
                  // Is it a value within our criteria
                  ++$returnValue;
              }
          }
  
          return $returnValue;
      }
docs: COUNTIF.
  
  Counts the number of cells that contain numbers within the list of arguments
  
  Excel Function:
  COUNTIF(value1[,value2[, ...]],condition)
  
  @category Statistical Functions
  
  @param mixed $aArgs Data values
  @param string $condition the criteria that defines which cells will be counted
  
  @return int