php数组合并：＋运算符、array_merge、array_merge_recursive的区别分析

$a = array(
    'a',
);
$b = array(
    'u',
);
$c = $a + $b;
var_dump($c);

输出:

$a = array(
    66=>'a',
);
$b = array(
    60=>'u',
    66=>'c'
);
$c = $a + $b;
var_dump($c);

输出:

$a = array(
    1=>'a',
    2=>'b',
    'c'=>'c',
    'd'=>'d',
);
$b = array(
    1=>'u',
    3=>'v',
    'c'=>'w',
    'd'=>'x',
    'y'=>'y',
    60=>'z',
);
$c = $a + $b;
var_dump($c);
?>

输出:

$a = array(
    'a',
);
$b = array(
    'u',
);
$c = array_merge($a, $b);
var_dump($c);

输出:

$a = array(
    66=>'a',
);
$b = array(
    60=>'u',
    66=>'c'
);
$c = array_merge($a, $b);
var_dump($c);

输出:

$a = array(
    1=>'a',
    2=>'b',
    'c'=>'c',
    'd'=>'d',
);
$b = array(
    1=>'u',
    3=>'v',
    'c'=>'w',
    'd'=>'x',
    'y'=>'y',
    60=>'z',
);
$c = array_merge($a, $b);
var_dump($c);

输出:

$a = array(
    'a',
);
$b = array(
    'u',
);
$c = array_merge_recursive($a, $b);
var_dump($c);

输出:

$a = array(
    'a',
);
$b = array(
    'u',
);
$c = array_merge_recursive($a, $b);
var_dump($c);

输出:

$a = array(
    1=>'a',
    2=>'b',
    'c'=>'c',
    'd'=>'d',
);
$b = array(
    1=>'u',
    3=>'v',
    'c'=>'w',
    'd'=>'x',
    'y'=>'y',
    60=>'z',
);
$c = array_merge_recursive($a, $b);
var_dump($c);

输出:

array(8) { [0]=> string(1) "a" [1]=> string(1) "b" ["c"]=> array(2) { [0]=> string(1) "c" [1]=> string(1) "w" } ["d"]=> array(2) { [0]=> string(1) "d" [1]=> string(1) "x" } [2]=> string(1) "u" [3]=> string(1) "v" ["y"]=> string(1) "y" [4]=> string(1) "z" }