1. <?php
  3. /**
  4. * Synchronizes resources of arrays for a local utility with limited memory usage.
  5. *
  6. * This function iterates through multiple arrays, synchronizing their elements
  7. * based on a provided key. It's designed for scenarios where loading entire
  8. * arrays into memory is undesirable, especially with large datasets.
  9. *
  10. * @param array $arrays An array of arrays to synchronize. Each inner array
  11. * should have a common key.
  12. * @param string $key The key to use for synchronizing the arrays.
  13. * @return array|null A new array containing the synchronized data. Returns null on error.
  14. */
  15. function syncArrays(array $arrays, string $key): ?array
  16. {
  17. if (empty($arrays)) {
  18. return []; // Return empty array if no input arrays
  19. }
  21. $synchronizedData = [];
  23. // Get the keys from the first array to use as the basis for synchronization
  24. $keys = array_keys($arrays[0]);
  26. foreach ($keys as $key_value) {
  27. $values = []; // Store values for a specific key
  29. // Iterate through all arrays to find values for the current key
  30. foreach ($arrays as $array) {
  31. if (isset($array[$key])) {
  32. $values[] = $array[$key];
  33. } else {
  34. $values[] = null; // Handle missing keys gracefully
  35. }
  36. }
  38. // Find the unique values for the current key
  39. $uniqueValues = array_values(array_unique($values));
  41. // Build the synchronized data for the current key
  42. foreach ($uniqueValues as $value) {
  43. $synchronizedData[$key_value] = $value;
  44. }
  45. }
  46. return $synchronizedData;
  47. }
  51. /**
  52. * Example usage (demonstrates memory efficiency)
  53. */
  55. // Simulate large arrays
  56. $array1 = [];
  57. for ($i = 0; $i < 1000; $i++) {
  58. $array1[$i] = 'value_' . $i;
  59. }
  61. $array2 = [];
  62. for ($i = 500; $i < 1500; $i++) {
  63. $array2[$i] = 'value_' . $i;
  64. }
  66. $array3 = [];
  67. for ($i = 1000; $i < 2000; $i++) {
  68. $array3[$i] = 'value_' . $i;
  69. }
  72. $arrays = [$array1, $array2, $array3];
  74. $synchronized = syncArrays($arrays, 'id');
  76. if ($synchronized !== null) {
  77. print_r($synchronized);
  78. } else {
  79. echo "Error during synchronization.\n";
  80. }
  83. ?>

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