PHP:合并两个数组，同时保留键，而不是驯鹿?

小开

最佳答案

你可以简单地“添加”数组:

>> $a = array(1, 2, 3);
array (
0 => 1,
1 => 2,
2 => 3,
)
>> $b = array("a" => 1, "b" => 2, "c" => 3)
array (
'a' => 1,
'b' => 2,
'c' => 3,
)
>> $a + $b
array (
0 => 1,
1 => 2,
2 => 3,
'a' => 1,
'b' => 2,
'c' => 3,
)

小开

考虑到你已经

$replaced = array('1' => 'value1', '4' => 'value4');
$replacement = array('4' => 'value2', '6' => 'value3');

执行$merge = $replacement + $replaced;将输出:

Array('4' => 'value2', '6' => 'value3', '1' => 'value1');

sum中的第一个数组将在最终输出中有值。

执行$merge = $replaced + $replacement;将输出:

Array('1' => 'value1', '4' => 'value4', '6' => 'value3');

小开

我只是想增加另一种可能性，在保留键的同时进行归并。

除了使用+符号向现有数组添加键/值外，您还可以执行array_replace。

$a = array('foo' => 'bar', 'some' => 'string', 'me' => 'is original');
$b = array(42 => 'answer to the life and everything', 1337 => 'leet', 'me' => 'is overridden');


$merged = array_replace($a, $b);

结果将是:

Array
(
[foo] => bar
[some] => string
[me] => is overridden
[42] => answer to the life and everything
[1337] => leet
)

相同的键将被后面的数组覆盖。
还有一个array_replace_recursive，它也为子数组执行此操作

Live example on 3v4l.org

小开

可以通过+操作符轻松添加或合并两个数组，而不改变它们的原始索引。这将非常有助于在laravel和codeigniter选择下拉菜单。

 $empty_option = array(
''=>'Select Option'
);


$option_list = array(
1=>'Red',
2=>'White',
3=>'Green',
);


$arr_option = $empty_option + $option_list;

输出将是:

$arr_option = array(
''=>'Select Option'
1=>'Red',
2=>'White',
3=>'Green',
);

小开

试试array_replace_recursive或array_replace函数

$a = array('userID' => 1, 'username'=> 2);
array (
userID => 1,
username => 2
)
$b = array('userID' => 1, 'companyID' => 3);
array (
'userID' => 1,
'companyID' => 3
)
$c = array_replace_recursive($a,$b);
array (
userID => 1,
username => 2,
companyID => 3
)

http://php.net/manual/en/function.array-replace-recursive.php

小开

OP.的要求是保存键(keep键)和不重叠(我认为覆盖)。在某些情况下，例如数字键，这是可能的，但如果字符串键，这似乎是不可能的。

如果你使用array_merge()，数字键将总是重新索引或重新编号。

如果你使用array_replace()， array_replace_recursive()，它将从右向左重叠或覆盖。在第一个数组上具有相同键的值将被第二个数组替换。

如果你使用$array1 + $array2作为注释，如果键是相同的，那么它将保留第一个数组的值，但删除第二个数组。

自定义函数。

这是我刚刚写的函数，满足同样的要求。你可以自由地用于任何目的。

/**
* Array custom merge. Preserve indexed array key (numbers) but overwrite string key (same as PHP's `array_merge()` function).
*
* If the another array key is string, it will be overwrite the first array.<br>
* If the another array key is integer, it will be add to first array depend on duplicated key or not.
* If it is not duplicate key with the first, the key will be preserve and add to the first array.
* If it is duplicated then it will be re-index the number append to the first array.
*
* @param array $array1 The first array is main array.
* @param array ...$arrays The another arrays to merge with the first.
* @return array Return merged array.
*/
function arrayCustomMerge(array $array1, array ...$arrays): array
{
foreach ($arrays as $additionalArray) {
foreach ($additionalArray as $key => $item) {
if (is_string($key)) {
// if associative array.
// item on the right will always overwrite on the left.
$array1[$key] = $item;
} elseif (is_int($key) && !array_key_exists($key, $array1)) {
// if key is number. this should be indexed array.
// and if array 1 is not already has this key.
// add this array with the key preserved to array 1.
$array1[$key] = $item;
} else {
// if anything else...
// get all keys from array 1 (numbers only).
$array1Keys = array_filter(array_keys($array1), 'is_int');
// next key index = get max array key number + 1.
$nextKeyIndex = (intval(max($array1Keys)) + 1);
unset($array1Keys);
// set array with the next key index.
$array1[$nextKeyIndex] = $item;
unset($nextKeyIndex);
}
}// endforeach; $additionalArray
unset($item, $key);
}// endforeach;
unset($additionalArray);


return $array1;
}// arrayCustomMerge

测试。

<?php
$array1 = [
'cat',
'bear',
'fruitred' => 'apple',
3 => 'dog',
null => 'null',
];
$array2 = [
1 => 'polar bear',
20 => 'monkey',
'fruitred' => 'strawberry',
'fruityellow' => 'banana',
null => 'another null',
];


// require `arrayCustomMerge()` function here.


function printDebug($message)
{
echo '<pre>';
print_r($message);
echo '</pre>' . PHP_EOL;
}


echo 'array1: <br>';
printDebug($array1);
echo 'array2: <br>';
printDebug($array2);




echo PHP_EOL . '<hr>' . PHP_EOL . PHP_EOL;




echo 'arrayCustomMerge:<br>';
$merged = arrayCustomMerge($array1, $array2);
printDebug($merged);




assert($merged[0] == 'cat', 'array key 0 should be \'cat\'');
assert($merged[1] == 'bear', 'array key 1 should be \'bear\'');
assert($merged['fruitred'] == 'strawberry', 'array key \'fruitred\' should be \'strawberry\'');
assert($merged[3] == 'dog', 'array key 3 should be \'dog\'');
assert(array_search('another null', $merged) !== false, '\'another null\' should be merged.');
assert(array_search('polar bear', $merged) !== false, '\'polar bear\' should be merged.');
assert($merged[20] == 'monkey', 'array key 20 should be \'monkey\'');
assert($merged['fruityellow'] == 'banana', 'array key \'fruityellow\' should be \'banana\'');

结果。

array1:


Array
(
[0] => cat
[1] => bear
[fruitred] => apple
[3] => dog
[] => null
)


array2:


Array
(
[1] => polar bear
[20] => monkey
[fruitred] => strawberry
[fruityellow] => banana
[] => another null
)


---
arrayCustomMerge:


Array
(
[0] => cat
[1] => bear
[fruitred] => strawberry
[3] => dog
[] => another null
[4] => polar bear
[20] => monkey
[fruityellow] => banana
)