php +与array_merge的区别

1. $a = array('a', 'b');
   $b = array('c', 'b');
   $c = $a + $b;
   print_r($c);
   print_r(array_merge($a, $b));
   

2. $a = array(0 => 'a', 1 => 'b');
   $b = array(0 => 'c', 1 => 'b');
   $c = $a + $b;
   print_r($c);
   print_r(array_merge($a, $b));
   

3. $a = array('a', 'b');
   $b = array('0' => 'c', 1 => 'b');
   $c = $a + $b;
   print_r($c);
   print_r(array_merge($a, $b));
   

4. $a = array(0 => 'a', 1 => 'b');
   $b = array('0' => 'c', '2' => 'b');
   $c = $a + $b;
   print_r($c);
   print_r(array_merge($a, $b));

1. Array
   (
   	[0] => a
   	[1] => b
   )
   Array
   (
   	[0] => a
   	[1] => b
   	[2] => c
   	[3] => b
   )
   		

2. Array
   (
   	[0] => a
   	[1] => b
   )
   Array
   (
   	[0] => a
   	[1] => b
   	[2] => c
   	[3] => b
   )
   		

3. Array
   (
   	[0] => a
   	[1] => b
   )
   Array
   (
   	[0] => a
   	[1] => b
   	[2] => c
   	[3] => b
   )
   		

4. Array
   (
   	[0] => a
   	[1] => b
   	[2] => b
   )
   Array
   (
   	[0] => a
   	[1] => b
   	[2] => c
   	[3] => b
   )
   		

结论：+键值合并，merge值累加