How to Create a Recursive Diff for Array Structures with Color-Coded Differences?

Comparing Array Structures using a Recursive Diff Algorithm

Question:

How can you generate a recursive diff of two arrays, where matching elements are marked green and non-matching elements are marked red?

Answer:

To perform a recursive diff, which compares arrays recursively, you can utilize a custom function like the one described in the comments of the PHP array_diff function:

function arrayRecursiveDiff($aArray1, $aArray2) {
  $aReturn = array();

  foreach ($aArray1 as $mKey => $mValue) {
    if (array_key_exists($mKey, $aArray2)) {
      if (is_array($mValue)) {
        $aRecursiveDiff = arrayRecursiveDiff($mValue, $aArray2[$mKey]);
        if (count($aRecursiveDiff)) { $aReturn[$mKey] = $aRecursiveDiff; }
      } else {
        if ($mValue != $aArray2[$mKey]) {
          $aReturn[$mKey] = $mValue;
        }
      }
    } else {
      $aReturn[$mKey] = $mValue;
    }
  }
  return $aReturn;
}

This function iterates through the keys and values of the first array, checks if the key exists in the second array, and handles the comparison based on the data type. If there is a structural or value mismatch, the result is added to the $aReturn array.

Benefits of Recursive Diff:

• Provides a visual representation of differences between two arrays.
• Allows for comparisons at any level of array structure, enabling thorough testing of complex data.
• Facilitates debugging and ensuring the correctness of updated methods.

Implementation Considerations:

• The function currently handles two arrays at a time. For larger sets, you can run the diff sequentially.
• The comparison method only checks for key existence and equality, so additional customization may be required based on your specific needs.

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