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Differences Between: [Versions 400 and 401] [Versions 400 and 402] [Versions 400 and 403]

   1  <?php
   2  
   3  namespace PhpOffice\PhpSpreadsheet\Calculation\Statistical;
   4  
   5  use PhpOffice\PhpSpreadsheet\Calculation\Exception;
   6  use PhpOffice\PhpSpreadsheet\Calculation\Functions;
   7  
   8  class Standardize extends StatisticalValidations
   9  {
  10      /**
  11       * STANDARDIZE.
  12       *
  13       * Returns a normalized value from a distribution characterized by mean and standard_dev.
  14       *
  15       * @param float $value Value to normalize
  16       * @param float $mean Mean Value
  17       * @param float $stdDev Standard Deviation
  18       *
  19       * @return float|string Standardized value, or a string containing an error
  20       */
  21      public static function execute($value, $mean, $stdDev)
  22      {
  23          $value = Functions::flattenSingleValue($value);
  24          $mean = Functions::flattenSingleValue($mean);
  25          $stdDev = Functions::flattenSingleValue($stdDev);
  26  
  27          try {
  28              $value = self::validateFloat($value);
  29              $mean = self::validateFloat($mean);
  30              $stdDev = self::validateFloat($stdDev);
  31          } catch (Exception $e) {
  32              return $e->getMessage();
  33          }
  34  
  35          if ($stdDev <= 0) {
  36              return Functions::NAN();
  37          }
  38  
  39          return ($value - $mean) / $stdDev;
  40      }
  41  }