PHP 連想配列の連結

配列および連想配列の連結について、ちょっと調べた。

(1) + 要素の連結

$test = array('A');
$test += array('A');
-------------------------------
array(
(int) 0 => 'A'
)

(2) + 要素の連結

$test = array(0=>'A');
$test += array(1=>'A');
-------------------------------
array(
(int) 0 => 'A',
(int) 1 => 'A'
)

(3) array_push 要素の追加

$test = array('A');
array_push($test, 'A');
-------------------------------
array(
	(int) 0 => 'A',
	(int) 1 => 'A'
)

(4) array_push 要素の追加

$test = array(0=>'A');
array_push($test, array(1=>'A'));
-------------------------------
array(
	(int) 0 => 'A',
	(int) 1 => array(
		(int) 1 => 'A'
	)
)

(5) array_merge 要素の連結

$test = array('a'=>'A');
$test = array_merge($test, array('a'=>'A'));
-------------------------------
array(
	'a' => 'A'
)

(6) array_merge 要素の連結

$test = array('a'=>'A');
$test = array_merge($test, array('b'=>'A'));
-------------------------------
array(
	'a' => 'A',
	'b' => 'A'
)

(7) array_merge 要素の連結

		
$test = array(0=>'A');
$test = array_merge($test, array(0=>'A'));
-------------------------------
array(
	(int) 0 => 'A',
	(int) 1 => 'A'
)

(8) array_merge 要素の連結

$test = array(1=>'A');
$test = array_merge($test, array(5=>'A'));
-------------------------------
array(
	(int) 0 => 'A',
	(int) 1 => 'A'
)