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  1. <?php
  2.  
  3. $data=['Fe+2HCl'=>'FeCl2+H2', 'Zn0+Cl2'=>'ZnCl2', '2H2+O2'=>'2H2O', '2H2O' => '2H2+O2'];
  4.  
  5. function foo (array $a) {
  6. 	$result = [];
  7. 	foreach ($a as $key=>$value) {
  8. 		$elems=explode('+',$value);
  9. 		foreach ($elems as &$el)
  10. 		  $el = preg_replace ('/^\d*/', '', trim($el));
  11. 		$result = array_merge ($result, $elems);
  12. 	}
  13. 	return array_unique ($result);
  14. }
  15.  
  16. var_dump (foo ($data));
Success #stdin #stdout 0.01s 20568KB
comments (?)
stdin 
Standard input is empty
stdout 
array(5) {
  [0]=>
  string(5) "FeCl2"
  [1]=>
  string(2) "H2"
  [2]=>
  string(5) "ZnCl2"
  [3]=>
  string(3) "H2O"
  [5]=>
  string(2) "O2"
}
https://ideone.com/GQrHIL
language:
PHP (php 7.3.5)
created:
11 years ago
visibility:
public

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