PHP php中数据合并“+”与array_merge（）的区别

PHP中两个数组合并可以使用+或者array_merge，下面我们来谈谈他们的区别:

1）键名为数字时，array_merge()后面的值将不会覆盖原来的值，而是附加到后面，但＋合并数组则会把最先出现的值作为最终结果返回，而把后面的数组拥有相同键名的那些值“抛弃”掉（不是覆盖）;

2）键名为字符串时，array_merge()此时会覆盖掉前面相同键名的值，但＋仍然把最先出现的值作为最终结果返回，而把后面的数组拥有相同键名的那些值“抛弃”掉（不是覆盖）;

For example:

$arr=array('A','B','C','D');
$arr2=array('E','F','G','H');

$var=array_merge($arr,$arr2);
$var2=$arr+$arr2;
print_r($var);
echo "<br>";
print_r($var2);
echo "<p>";

$arr3=array("1"=>"A","2"=>"B","3"=>"C","4"=>"D");
$arr4=array("1"=>"E","2"=>"F","3"=>"G","4"=>"H");

$var3=$arr3+$arr4;
print_r($var3);
echo "<br>";
print_r(array_merge($arr3,$arr4));
echo "<p>";

$arry=array("A"=>"A","B"=>"B","C"=>"C","D"=>"D");
$arry2=array("A"=>"E","B"=>"F","C"=>"G","D"=>"H");

$var4=$arry+$arry2;
print_r($var4);
echo "<br>";
print_r(array_merge($arry+$arry2));

output:

Array ( [0] => A [1] => B [2] => C [3] => D [4] => E [5] => F [6] => G [7] => H )
Array ( [0] => A [1] => B [2] => C [3] => D )

Array ( [1] => A [2] => B [3] => C [4] => D )
Array ( [0] => A [1] => B [2] => C [3] => D [4] => E [5] => F [6] => G [7] => H )

Array ( [A] => A [B] => B [C] => C [D] => D )
Array ( [A] => A [B] => B [C] => C [D] => D )

参考资料：http://www.php-note.com/article/detail/138