在 PHP 中更改关联数组中的键
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Change key in associative array in PHP
提问by Hommer Smith
Say I have an array like this:
假设我有一个这样的数组：
array(2) {
[0]=> array(2) {
["n"]=> string(4) "john"
["l"]=> string(3) "red"
}
[1]=> array(2) {
["n"]=> string(5) "nicel"
["l"]=> string(4) "blue"
}
}
How would I change the keys of the inside arrays? Say, I want to change "n" for "name" and "l" for "last_name". Taking into account that it can happen than an array doesn't have a particular key.
我将如何更改内部数组的键？比如说，我想将“n”更改为“name”，将“l”更改为“last_name”。考虑到它可能发生而不是数组没有特定的键。
采纳答案by anydasa
Using array_walk
使用 array_walk
array_walk($array, function (& $item) {
$item['new_key'] = $item['old_key'];
unset($item['old_key']);
});
回答by Carl Owens
Something like this maybe:
可能是这样的：
if (isset($array['n'])) {
$array['name'] = $array['n'];
unset($array['n']);
}
NOTE: this solution will change the order of the keys. To preserve the order, you'd have to recreate the array.
注意：此解决方案将更改键的顺序。要保留顺序，您必须重新创建数组。
回答by Alberto Arena
You could have:
你可以有：
- an array that maps the key exchange (to make the process parametrizable)
- a loop the processes the original array, accessing to every array item by reference
- 映射密钥交换的数组（使过程可参数化）
- 循环处理原始数组，通过引用访问每个数组项
E.g.:
例如：
$array = array( array('n'=>'john','l'=>'red'), array('n'=>'nicel','l'=>'blue') );
$mapKeyArray = array('n'=>'name','l'=>'last_name');
foreach( $array as &$item )
{
foreach( $mapKeyArray as $key => $replace )
{
if (key_exists($key,$item))
{
$item[$replace] = $item[$key];
unset($item[$key]);
}
}
}
In such a way, you can have other replacements simply adding a couple key/value to the $mapKeyArrayvariable.
通过这种方式，您可以进行其他替换，只需向$mapKeyArray变量添加几个键/值即可。
This solution also works if some key is not available in the original array
如果某些键在原始数组中不可用，此解决方案也适用
回答by Ed Heal
回答by Richard A Quadling
Renaming the key AND keeping the ordering consistent (the later was important for the use case that the following code was written).
重命名键并保持顺序一致（后者对于编写以下代码的用例很重要）。
<?php
/**
* Rename a key and preserve the key ordering.
*
* An E_USER_WARNING is thrown if there is an problem.
*
* @param array &$data The data.
* @param string $oldKey The old key.
* @param string $newKey The new key.
* @param bool $ignoreMissing Don't raise an error if the $oldKey does not exist.
* @param bool $replaceExisting Don't raise an error if the $newKey already exists.
*
* @return bool True if the rename was successful or False if the old key cannot be found or the new key already exists.
*/
function renameKey(array &$data, $oldKey, $newKey, $ignoreMissing = false, $replaceExisting = false)
{
if (!empty($data)) {
if (!array_key_exists($oldKey, $data)) {
if ($ignoreMissing) {
return false;
}
return !trigger_error('Old key does not exist', E_USER_WARNING);
} else {
if (array_key_exists($newKey, $data)) {
if ($replaceExisting) {
unset($data[$newKey]);
} else {
return !trigger_error('New key already exists', E_USER_WARNING);
}
}
$keys = array_keys($data);
$keys[array_search($oldKey, array_map('strval', $keys))] = $newKey;
$data = array_combine($keys, $data);
return true;
}
}
return false;
}
And some unit tests (PHPUnit being used, but hopefully understandable as the purpose of the tests).
还有一些单元测试（正在使用 PHPUnit，但希望可以理解为测试的目的）。
public function testRenameKey()
{
$newData = $this->data;
$this->assertTrue(Arrays::renameKey($newData, 200, 'TwoHundred'));
$this->assertEquals(
[
100 => $this->one,
'TwoHundred' => $this->two,
300 => $this->three,
],
$newData
);
}
public function testRenameKeyWithEmptyData()
{
$newData = [];
$this->assertFalse(Arrays::renameKey($newData, 'junk1', 'junk2'));
}
public function testRenameKeyWithExistingNewKey()
{
Arrays::renameKey($this->data, 200, 200);
$this->assertError('New key already exists', E_USER_WARNING);
}
public function testRenameKeyWithMissingOldKey()
{
Arrays::renameKey($this->data, 'Unknown', 'Unknown');
$this->assertError('Old key does not exist', E_USER_WARNING);
}
public function testRenameKeyWithMixedNumericAndStringIndicies()
{
$data = [
'nice', // Index 0
'car' => 'fast',
'none', // Index 1
];
$this->assertTrue(Arrays::renameKey($data, 'car', 2));
$this->assertEquals(
[
0 => 'nice',
2 => 'fast',
1 => 'none',
],
$data
);
}
The AssertError assertion is available for PHPUnit from https://github.com/digitickets/phpunit-errorhandler
AssertError 断言可用于 PHPUnit，来自https://github.com/digitickets/phpunit-errorhandler
回答by Davin
function arrayReplaceKey($array, $oldKey, $newKey) {
$r = array();
foreach ($array as $k => $v) {
if ($k === $oldKey) $k = $newKey;
$r[$k] = $v;
}
return $r;
}
回答by Radley Sustaire
Here is a solution to change the key of an arrayand also keep the original position within the array. It is intended for associative arrays. In my case the values were objects but I've simplified this example.
这是更改数组键并保持数组中原始位置的解决方案。它用于关联数组。在我的例子中，值是对象，但我已经简化了这个例子。
// Our array
$fields = array(
'first_name' => 'Radley',
'last_name' => 'Sustaire',
'date' => '6/26/2019', // <== Want to rename the key from "date" to "date_db"
'amazing' => 'yes',
);
// Get the field value
$date_field = $fields['date'];
// Get the key position in the array (numeric)
$key_position = array_search( 'date', array_keys($fields) );
// Remove the original value
unset($fields['date']);
// Add the new value back in, with the new key, at the old position
$fields = array_merge(
array_slice( $fields, 0, $key_position, true ),
array( 'date_db' => $date_field ), // Notice the new key ends with "_db"
array_slice( $fields, $key_position, null, true )
);
/*
Input:
Array(
[first_name] => Radley
[last_name] => Sustaire
[date] => 6/26/2019
[amazing] => yes
)
Output:
Array(
[first_name] => Radley
[last_name] => Sustaire
[date_db] => 6/26/2019
[amazing] => yes
)
*/
回答by Lajos Meszaros
You could use the array_flipfunction:
您可以使用array_flip函数：
$original = array('n'=>'john','l'=>'red');
$flipped = array_flip($original);
foreach($flipped as $k => $v){
$flipped[$k] = ($v === 'n' ? 'name' : ($v === 'l' ? 'last_name' : $v));
}
$correctedOriginal = array_flip($flipped);
