数字索引为下标，并且两个数组键名不同
array_merge()
$arr1 = array(3=>'php',6=>'mysql',9=>'apache');
$arr2 = array('php','mysql','apache');
print_r(array_merge($arr1,$arr2));
结果是：
Array
(
[0] => php
[1] => mysql
[2] => apache
[3] => php
[4] => mysql
[5] => apache
)
键名会以连续方式重新索引。
"+" 号实现
$arr1 = array(3=>'php',6=>'mysql',9=>'apache');
$arr2 = array('php','mysql','apache');
print_r($arr1+$arr2);
结果是：
Array
(
[3] => php
[6] => mysql
[9] => apache
[0] => php
[1] => mysql
[2] => apache
)
数字索引为下标，两个数组键名相同的情况
"+"号
$arr1 = array('php','mysql','apache');
$arr2 = array('java','oracle','nginx');
print_r($arr1+$arr2);
结果是：
Array
(
[0] => php
[1] => mysql
[2] => apache
)
array_merge()
print_r(array_merge($arr1,$arr2));
结果是：
Array
(
[0] => php
[1] => mysql
[2] => apache
[3] => java
[4] => oracle
[5] => nginx
)
非索引为下标，两个数组键名相同的情况
array_merge()
$arr1 = array('lan'=>'php','db'=>'mysql','server'=>'apache');
$arr2 = array('lan'=>'java','db'=>'oracle','server'=>'nginx');
print_r(array_merge($arr1,$arr2));
结果是：
Array
(
[lan] => java
[db] => oracle
[server] => nginx
）
"+" 号
print_r($arr1+$arr2);
Array
(
[lan] => php
[db] => mysql
[server] => apache
)
