PHP で 2 つの配列をマージする 2 つの方法

echo "rn最初のケースrn";
$a=array(1,2,3,4,5,6);
$b=array( 7, 8,9);

$c=array_merge ($a,$b);
print_r($c);
$c=$a+$b;
print_r($c);
$c=$b+ $a ;
print_r($c);
echo "rn2 番目のケース rn";
$a=array('a','b','c','d ','e' ,'f');
$b=array('a','x','y');

$c=array_merge ($a,$b);
print_r($c) ;
$c= $a+$b;
print_r($c);
$c=$b+$a;
print_r($c);

echo "rn3番目のケースrn";

$a= array(
 1=>' a',
 2=>'b',
 3=>'c',
 4=>'d',
 5=>'e',
 6=>'f');
 $b=array(
 1=>'a',
 7=>'x',
 8=>'y');

$c=array_merge ($a ,$b);
print_r( $c);
$c=$a+$b;
print_r($c);
$c=$b+$a;
print_r($c);
?

出力結果: 最初の状況 配列 ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 [5] => 6 [6] => 7 [7] => 8 [8] => 9 ) 配列 ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 [5] => 6 ) 配列 ( [0] => 7 [1] => 8 [2] => 9 [3] => 4 [4] => 5 [5] => 6 ) 2番目のケース 配列 ( [0] => a [1] => b [2] => c [3] => d [4] =>e [5] => f [6] => a [7] => × [8] => y ) 配列 ( [0] => a [1] => b [2] => c [3] => d [4] =>e [5] => f ) 配列 ( [0] => a [1] => × [2] => y [3] => d [4] =>e [5] => f ) 3番目の状況 配列 ( [0] => a [1] => b [2] => c [3] => d [4] => e [5] => f [6] => a [7] => × [8] => y ) 配列 ( [1] => a [2] => b [3] => c [4] => d [5] =>e [6] => f [7] => × [8] => y ) 配列 ( [1] => a [7] => × [8] => y [2] => b [3] => c [4] => d [5] =>e [6] => f )