PHP数组合并之array_merge和数组相加

$programmer1 = array("a"=>"PHP程序员","b"=>"JAVA程序员","IOS程序员");
$programmer2 = array("c" =>"安卓程序员","d" => "ASP程序员","前端","a"=> "DBA");

$programmer3 = array_merge($programmer1,$programmer2);
var_dump($programmer3);

array(6) {
["a"]=>
string(3) "DBA"
["b"]=>
string(13) "JAVA程序员"
[0]=>
string(12) "IOS程序员"
["c"]=>
string(15) "安卓程序员"
["d"]=>
string(12) "ASP程序员"
[1]=>
string(6) "前端"
}

$programmer4 = $programmer1 + $programmer2;
var_dump($programmer4);

array(5) {
["a"]=>
string(12) "PHP程序员"
["b"]=>
string(13) "JAVA程序员"
[0]=>
string(12) "IOS程序员"
["c"]=>
string(15) "安卓程序员"
["d"]=>
string(12) "ASP程序员"
}