1）键名为数字时，array_merge()不会覆盖掉原来的值，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）键名为字符时，＋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，但array_merge()此时会覆盖掉前面相同键名的值
需要注意的是数组键形式 '数字' 等价于 数字
$c = $a + $b;
var_dump($a); var_dump(array_merge($a, $b));
结果:
array(2) {
[0]=> string(1) "a"
[1]=> string(1) "b"
}
array(4) {
[0]=> string(1) "a"
[1]=> string(1) "b"
[2]=> string(1) "c"
[3]=> string(1) "d"
}
-----------------------------------------------------
$a = array(0 => 'a', 1 => 'b'); $b = array(0 => 'c', 1 => 'b');$c = $a + $b;
var_dump($c); var_dump(array_merge($a, $b));
结果:
array(2) {
[0]=> string(1) "a"
[1]=> string(1) "b"
}
array(4) {
[0]=> string(1) "a"
[1]=> string(1) "b"
[2]=> string(1) "c"
[3]=> string(1) "b"
}
-----------------------------------------------------
$a = array('a', 'b'); $b = array('0' => 'c', 1 => 'b');$c = $a + $b;
var_dump($c); var_dump(array_merge($a, $b));
结果:
array(2) {
[0]=> string(1) "a"
[1]=> string(1) "b"
}
array(4) {
[0]=> string(1) "a"
[1]=> string(1) "b"
[2]=> string(1) "c"
[3]=> string(1) "b"
}
-----------------------------------------------------
$c = $a + $b;
var_dump($c); var_dump(array_merge($a, $b));
结果:
array(2) {
[0]=> string(1) "a"
[1]=> string(1) "b"
}
array(4) {
[0]=> string(1) "a"
[1]=> string(1) "b"
[2]=> string(1) "c"
[3]=> string(1) "b"
}
-----------------------------------------------------
$array1 = array('asd'=>'0'); $array2 = array('asd' => "data");
$result1 = $array1 + $array2 ;/*结果为$array1的值*/
var_dump($result1);
$result2 = array_merge($array1,$array2);/*结果为$array2*/
var_dump($result2);
结果:
array(1) {
["asd"]=> string(1) "0"
}
array(1) {
["asd"]=> string(4) "data"
}
结果
array
0 => string 'a' (length=1)
1 => string 'b' (length=1)
2 => string 'c' (length=1)
3 => string 'd' (length=1)
array
0 => string 'a' (length=1)
1 => string 'b' (length=1)
array
0 => string 'a' (length=1)
1 => string 'b' (length=1)
2 => string 'c' (length=1)
3 => string 'b' (length=1)
array
0 => string 'a' (length=1)
1 => string 'b' (length=1)
array
0 => string 'a' (length=1)
1 => string 'b' (length=1)
2 => string 'c' (length=1)
3 => string 'b' (length=1)
array
0 => string 'a' (length=1)
1 => string 'b' (length=1)
array
0 => string 'a' (length=1)
1 => string 'b' (length=1)
2 => string 'c' (length=1)
3 => string 'b' (length=1)