PHP中array_merge合并两个数组的程序

原创
2016-06-13 10:15:46 833浏览

合并数据在php中我们利用array_merge()函数来实现,array_merge() 函数把两个或多个数组合并为一个数组。 如果键名有重复,该键的键值为最后一个键名对应的值(后面的覆盖前面的)。如果数组是数字索引的,则键名会以连续方式重新索引。

代码如下 复制代码


echo "rn第一种情况rn";
$a=array(1,2,3,4,5,6);
$b=array(7,8,9);

$c=array_merge ($a,$b);
print_r($c);
$c=$a+$b;
print_r($c);
$c=$b+$a;
print_r($c);


echo "rn第二种情况rn";
$a=array('a','b','c','d','e','f');
$b=array('a','x','y');

$c=array_merge ($a,$b);
print_r($c);
$c=$a+$b;
print_r($c);
$c=$b+$a;
print_r($c);


echo "rn第三种情况rn";

$a=array(
1=>'a',
2=>'b',
3=>'c',
4=>'d',
5=>'e',
6=>'f');
$b=array(
1=>'a',
7=>'x',
8=>'y');

$c=array_merge ($a,$b);
print_r($c);
$c=$a+$b;
print_r($c);
$c=$b+$a;
print_r($c);
?>

结果如下:

第一种情况
Array
(
[0] => 1
[1] => 2
[2] => 3
[3] => 4
[4] => 5
[5] => 6
[6] => 7
[7] => 8
[8] => 9
)
Array
(
[0] => 1
[1] => 2
[2] => 3
[3] => 4
[4] => 5
[5] => 6
)
Array
(
[0] => 7
[1] => 8
[2] => 9
[3] => 4
[4] => 5
[5] => 6
)

第二种情况
Array
(
[0] => a
[1] => b
[2] => c
[3] => d
[4] => e
[5] => f
[6] => a
[7] => x
[8] => y
)
Array
(
[0] => a
[1] => b
[2] => c
[3] => d
[4] => e
[5] => f
)
Array
(
[0] => a
[1] => x
[2] => y
[3] => d
[4] => e
[5] => f
)

第三种情况
Array
(
[0] => a
[1] => b
[2] => c
[3] => d
[4] => e
[5] => f
[6] => a
[7] => x
[8] => y
)
Array
(
[1] => a
[2] => b
[3] => c
[4] => d
[5] => e
[6] => f
[7] => x
[8] => y
)
Array
(
[1] => a
[7] => x
[8] => y
[2] => b
[3] => c
[4] => d
[5] => e
[6] => f
)

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


注释:如果仅仅向 array_merge() 函数输入了一个数组,且键名是整数,则该函数将返回带有整数键名的新数组,其键名以 0 开始进行重新索引

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