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  1. <?php
  2.         $arr = array(
  3.                         501=>"a",
  4.                         402=>"b",
  5.                         303=>"c",
  6.                         204=>"d",
  7.                         105=>"a",
  8.                 );
  9. 	/* 
  10. 		http://w...content-available-to-author-only...p.net/manual/en/function.array-flip.php
  11. 		array_flip:
  12. 			array_flip() returns an array in flip order, 
  13. 			i.e. keys from trans become values 
  14. 			and values from trans become keys. 
  15.  
  16. 			If a value has several occurrences, 
  17. 			the latest key will be used as its values, 
  18. 			and all others will be lost. 
  19. 	*/
  20. 	$arr2 = array_keys(array_flip(array_flip(array_reverse($arr,true))));
  21. 	foreach ($arr as $key1 => $value1) {
  22. 		/* 空の配列はFALSEなので注意 */
  23. 		if(array_search($key1,$arr2,true) === FALSE){
  24. 			continue;
  25. 		}
  26.  
  27. 		foreach ($arr as $key2 => $value2) {
  28. 			if($value1 !== $value2 || $key1 == $key2 ){
  29. 				continue;
  30. 			}
  31. 			print_r("dupe:" . $key2 . ":" . $value2 . "\n");
  32. 		}
  33. 	}
  34. ?>
Success #stdin #stdout 0.01s 13112KB
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dupe:105:a
https://ideone.com/jgb2R
language:
PHP (php 7.3.5)
created:
13 years ago
visibility:
secret

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