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PHP rename array keys in multidimensional array
(10 answers)
Closed last month.
When I var_dump on a variable called $tags (a multidimensional array) I get this:
Array
(
[0] => Array
(
[name] => tabbing
[url] => tabbing
)
[1] => Array
(
[name] => tabby ridiman
[url] => tabby-ridiman
)
[2] => Array
(
[name] => tables
[url] => tables
)
[3] => Array
(
[name] => tabloids
[url] => tabloids
)
[4] => Array
(
[name] => taco bell
[url] => taco-bell
)
[5] => Array
(
[name] => tacos
[url] => tacos
)
)
I would like to rename all array keys called "url" to be called "value". What would be a good way to do this?
You could use array_map() to do it.
$tags = array_map(function($tag) {
return array(
'name' => $tag['name'],
'value' => $tag['url']
);
}, $tags);
Loop through, set new key, unset old key.
foreach($tags as &$val){
$val['value'] = $val['url'];
unset($val['url']);
}
Talking about functional PHP, I have this more generic answer:
array_map(function($arr){
$ret = $arr;
$ret['value'] = $ret['url'];
unset($ret['url']);
return $ret;
}, $tag);
}
Recursive php rename keys function:
function replaceKeys($oldKey, $newKey, array $input){
$return = array();
foreach ($input as $key => $value) {
if ($key===$oldKey)
$key = $newKey;
if (is_array($value))
$value = replaceKeys( $oldKey, $newKey, $value);
$return[$key] = $value;
}
return $return;
}
foreach ($basearr as &$row)
{
$row['value'] = $row['url'];
unset( $row['url'] );
}
unset($row);
This should work in most versions of PHP 4+. Array map using anonymous functions is not supported below 5.3.
Also the foreach examples will throw a warning when using strict PHP error handling.
Here is a small multi-dimensional key renaming function. It can also be used to process arrays to have the correct keys for integrity throughout your app. It will not throw any errors when a key does not exist.
function multi_rename_key(&$array, $old_keys, $new_keys)
{
if(!is_array($array)){
($array=="") ? $array=array() : false;
return $array;
}
foreach($array as &$arr){
if (is_array($old_keys))
{
foreach($new_keys as $k => $new_key)
{
(isset($old_keys[$k])) ? true : $old_keys[$k]=NULL;
$arr[$new_key] = (isset($arr[$old_keys[$k]]) ? $arr[$old_keys[$k]] : null);
unset($arr[$old_keys[$k]]);
}
}else{
$arr[$new_keys] = (isset($arr[$old_keys]) ? $arr[$old_keys] : null);
unset($arr[$old_keys]);
}
}
return $array;
}
Usage is simple. You can either change a single key like in your example:
multi_rename_key($tags, "url", "value");
or a more complex multikey
multi_rename_key($tags, array("url","name"), array("value","title"));
It uses similar syntax as preg_replace() where the amount of $old_keys and $new_keys should be the same. However when they are not a blank key is added. This means you can use it to add a sort if schema to your array.
Use this all the time, hope it helps!
Very simple approach to replace keys in a multidimensional array, and maybe even a bit dangerous, but should work fine if you have some kind of control over the source array:
$array = [ 'oldkey' => [ 'oldkey' => 'wow'] ];
$new_array = json_decode(str_replace('"oldkey":', '"newkey":', json_encode($array)));
print_r($new_array); // [ 'newkey' => [ 'newkey' => 'wow'] ]
This doesn't have to be difficult in the least. You can simply assign the arrays around regardless of how deep they are in a multi-dimensional array:
$array['key_old'] = $array['key_new'];
unset($array['key_old']);
You can do it without any loop
Like below
$tags = str_replace("url", "value", json_encode($tags));
$tags = json_decode($tags, true);
class DataHelper{
private static function __renameArrayKeysRecursive($map = [], &$array = [], $level = 0, &$storage = []) {
foreach ($map as $old => $new) {
$old = preg_replace('/([\.]{1}+)$/', '', trim($old));
if ($new) {
if (!is_array($new)) {
$array[$new] = $array[$old];
$storage[$level][$old] = $new;
unset($array[$old]);
} else {
if (isset($array[$old])) {
static::__renameArrayKeysRecursive($new, $array[$old], $level + 1, $storage);
} else if (isset($array[$storage[$level][$old]])) {
static::__renameArrayKeysRecursive($new, $array[$storage[$level][$old]], $level + 1, $storage);
}
}
}
}
}
/**
* Renames array keys. (add "." at the end of key in mapping array if you want rename multidimentional array key).
* #param type $map
* #param type $array
*/
public static function renameArrayKeys($map = [], &$array = [])
{
$storage = [];
static::__renameArrayKeysRecursive($map, $array, 0, $storage);
unset($storage);
}
}
Use:
DataHelper::renameArrayKeys([
'a' => 'b',
'abc.' => [
'abcd' => 'dcba'
]
], $yourArray);
It is from duplicated question
$json = '[
{"product_id":"63","product_batch":"BAtch1","product_quantity":"50","product_price":"200","discount":"0","net_price":"20000"},
{"product_id":"67","product_batch":"Batch2","product_quantity":"50","product_price":"200","discount":"0","net_price":"20000"}
]';
$array = json_decode($json, true);
$out = array_map(function ($product) {
return array_merge([
'price' => $product['product_price'],
'quantity' => $product['product_quantity'],
], array_flip(array_filter(array_flip($product), function ($value) {
return $value != 'product_price' && $value != 'product_quantity';
})));
}, $array);
var_dump($out);
https://repl.it/#Piterden/Replace-keys-in-array
This is how I rename keys, especially with data that has been uploaded in a spreadsheet:
function changeKeys($array, $new_keys) {
$newArray = [];
foreach($array as $row) {
$oldKeys = array_keys($row);
$indexedRow = [];
foreach($new_keys as $index => $newKey)
$indexedRow[$newKey] = isset($oldKeys[$index]) ? $row[$oldKeys[$index]] : '';
$newArray[] = $indexedRow;
}
return $newArray;
}
Based on the great solution provided by Alex, I created a little more flexible solution based on a scenario I was dealing with. So now you can use the same function for multiple arrays with different numbers of nested key pairs, you just need to pass in an array of key names to use as replacements.
$data_arr = [
0 => ['46894', 'SS'],
1 => ['46855', 'AZ'],
];
function renameKeys(&$data_arr, $columnNames) {
// change key names to be easier to work with.
$data_arr = array_map(function($tag) use( $columnNames) {
$tempArray = [];
$foreachindex = 0;
foreach ($tag as $key => $item) {
$tempArray[$columnNames[$foreachindex]] = $item;
$foreachindex++;
}
return $tempArray;
}, $data_arr);
}
renameKeys($data_arr, ["STRATEGY_ID","DATA_SOURCE"]);
this work perfectly for me
$some_options = array();;
if( !empty( $some_options ) ) {
foreach( $some_options as $theme_options_key => $theme_options_value ) {
if (strpos( $theme_options_key,'abc') !== false) { //first we check if the value contain
$theme_options_new_key = str_replace( 'abc', 'xyz', $theme_options_key ); //if yes, we simply replace
unset( $some_options[$theme_options_key] );
$some_options[$theme_options_new_key] = $theme_options_value;
}
}
}
return $some_options;
I am trying to create a function to remove keys from a dynamic multidimensional array, i need to give:
removeByIndex(['hello', 'my', 'world']);
And then the function needs to do this:
unset($array['hello']['my']['world']);
The number of indexes are dynamic, example:
removeByIndex(['hello', 'my']); // Do: unset($array['hello']['my']);
removeByIndex(['hello']); // Do: unset($array['hello']);
I tried to use some foreach loops, but i didn't find a solution yet.
Any help will be welcome.
No need for eval() with a little bit of referencing.
/**
* Remove index from multi-dimensional array.
*
* #param array $array
* The array to remove the index from.
* #param array $indices
* Indexed array containing the indices chain up to the index that should be
* removed.
* #return
* The array with the index removed.
* #throws \InvalidArgumentException
* If the index does not exist within the array.
*/
function removeByIndex(array $array, array $indices) {
// Create a reference to the original array.
$a =& $array;
// Count all passed indices, remove one because arrays are zero based.
$c = count($indices) - 1;
// Iterate over all passed indices.
for ($i = 0; $i <= $c; ++$i) {
// Make sure the index to go down for deletion actually exists.
if (array_key_exists($indices[$i], $a)) {
// This is the target if we reached the last index that was passed.
if ($i === $c) {
unset($a[$indices[$i]]);
}
// Make sure we have an array to go further down.
elseif (is_array($a[$indices[$i]])) {
$a =& $a[$indices[$i]];
}
// Index does not exist since there is no array to go down any further.
else {
throw new \InvalidArgumentException("{$indices[$i]} does not exist.");
}
}
// Index does not exist, error.
else {
throw new \InvalidArgumentException("{$indices[$i]} does not exist.");
}
}
return $array;
}
print_r(removeByIndex(
[ "test1" => [ "test2" => [ "test3" => "test" ] ], "test4" => "test" ],
[ "test1", "test2", "test3" ]
));
Since I mentioned it in the comments, one could (micro-)optimize the function, but I advice against it, since it is less readable and might confuse some programmers.
<?php
function removeByIndex(array $array, array $indices) {
$a =& $array;
$c = count($indices) - 1;
$i = 0;
do {
if (array_key_exists($indices[$i], $a)) {
if ($i === $c) {
unset($a[$indices[$i]]);
return $array;
}
elseif (is_array($a[$indices[$i]])) {
$a =& $a[$indices[$i]];
}
else break;
}
else break;
}
while (++$i);
throw new \InvalidArgumentException("{$indices[$i]} does not exist.");
}
Based on the briliant #Fleshgrinder answer, i am using this final version:
function removeByIndex($vars, $indexes) {
if ( ! is_array($indexes)) {
throw new \Exception('Array expected');
}
$array = & $vars;
$qtd_indexes = count($indexes);
for ($i = 0; $i < $qtd_indexes; $i++) {
if ( ! array_key_exists($indexes[$i], $array)) {
throw new \Exception($indexes[$i] . " doesn't exist");
}
// Check if it is the target entry
if ($i === $qtd_indexes - 1) {
unset($array[$indexes[$i]]);
} elseif (is_array($array[$indexes[$i]])) { // Check if exists one more level
$array = & $array[$indexes[$i]];
} else {
// If it isn't the target and it isn't an array, throw exception
throw new \Exception("Content of '" . $indexes[$i] . "' isn't an array");
}
}
return $vars;
}
I was researched for a couple of hours for this solution, nowhere found an optimal solution. so, i wrote it by myself
function allow_keys($arr, $keys)
{
$saved = [];
foreach ($keys as $key => $value) {
if (is_int($key) || is_int($value)) {
$keysKey = $value;
} else {
$keysKey = $key;
}
if (isset($arr[$keysKey])) {
$saved[$keysKey] = $arr[$keysKey];
if (is_array($value)) {
$saved[$keysKey] = allow_keys($saved[$keysKey], $keys[$keysKey]);
}
}
}
return $saved;
}
use: example
$array = [
'key1' => 'kw',
'loaa'=> ['looo'],
'k' => [
'prope' => [
'prop' => ['proo', 'prot', 'loolooo', 'de'],
'prop2' => ['hun' => 'lu'],
],
'prop1' => [
],
],
];
call: example
allow_keys($array, ['key1', 'k' => ['prope' => ['prop' => [0, 1], 'prop2']]])
output:
Array ( [key1] => kw [k] => Array ( [prope] => Array ( [prop] => Array ( [0] => proo [1] => prot ) [prop2] => Array ( [hun] => lu ) ) ) )
so you get only needed keys from the multidimensional array. it is not limited only for "multidimensional", you can use it by passing an array like
['key1', 'loaa']
output you get:
Array ( [key1] => kw [loaa] => Array ( [0] => looo ) )
i'm writing it here for reason that this topic is one of the first when you type on google
recursive remove keys multidimensional php
hope someone helps this one, as i searched a lot, and nothing found.
cheers!
I have an array that is a object which I carry in session lifeFleetSelectedTrucksList
I also have objects of class fleetUnit
class fleetUnit {
public $idgps_unit = null;
public $serial = null;
}
class lifeFleetSelectedTrucksList {
public $arrayList = array();
}
$listOfTrucks = new lifeFleetSelectedTrucksList(); //this is the array that I carry in session
if (!isset($_SESSION['lifeFleetSelectedTrucksList'])) {
$_SESSION['lifeFleetSelectedTrucksList'] == null; //null the session and add new list to it.
} else {
$listOfTrucks = $_SESSION['lifeFleetSelectedTrucksList'];
}
I use this to remove element from array:
$listOfTrucks = removeElement($listOfTrucks, $serial);
And this is my function that removes the element and returns the array without the element:
function removeElement($listOfTrucks, $remove) {
for ($i = 0; $i < count($listOfTrucks->arrayList); $i++) {
$unit = new fleetUnit();
$unit = $listOfTrucks->arrayList[$i];
if ($unit->serial == $remove) {
unset($listOfTrucks->arrayList[$i]);
break;
} elseif ($unit->serial == '') {
unset($listOfTrucks->arrayList[$i]);
}
}
return $listOfTrucks;
}
Well, it works- element gets removed, but I have array that has bunch of null vaues instead. How do I return the array that contains no null elements? Seems that I am not suing something right.
I think what you mean is that the array keys are not continuous anymore. An array does not have "null values" in PHP, unless you set a value to null.
$array = array('foo', 'bar', 'baz');
// array(0 => 'foo', 1 => 'bar', 2 => 'baz');
unset($array[1]);
// array(0 => 'foo', 2 => 'baz');
Two approaches to this:
Loop over the array using foreach, not a "manual" for loop, then it won't matter what the keys are.
Reset the keys with array_values.
Also, removing trucks from the list should really be a method of $listOfTrucks, like $listOfTrucks->remove($remove). You're already using objects, use them to their full potential!
You can use array_filter
<?php
$entry = array(
0 => 'foo',
1 => false,
2 => -1,
3 => null,
4 => ''
);
print_r(array_filter($entry));
?>
output:
Array
(
[0] => foo
[2] => -1
)
I have several strings, how can I search the first value and get other values from it?
print_r or ?:
Array( [0] => Title,11,11 [1] => Would,22,22 [2] => Post,55,55 [3] => Ask,66,66 )
like:
If send for this array value Title and getting values Title,11,11
Or send Would getting values Would,22,22
Or send Post getting values Post,55,55
Or send Ask getting values Ask,66,66
How can do it?
Loop over the array with foreach and match the value with strpos.
suppose:
$arr = Array( [0] => Title,11,11 [1] => Would,22,22 [2] => Post,55,55 [3] => Ask,66,66 )
$string = 'Would';
then
//Call the function with the search value in $string and the actual array
$required_arr[$string] = search_my_array($string, $arr);
function($str , $array)
{
//Trace the complete array
for($i = 0; $i<count($array); $i++)
{
//Break the array using explode function based on ','
$arr_values[$i] = explode(',',$array[i])
if($str == $arr_values[$i][0]) // Match the First String with the required string
{
//On match return the array with the values contained in it
return array($arr_values[$i][1], $arr_values[$i][2]);
}
}
}
Now
$required_arr['Would'] // will hold Array([0] => 22 [1] => 22)
Write a function to search the array. This should work well enough
<?php
// test array
$arr = array('Title,11,11','Would,22,22','Post,55,55','Ask,66,66');
// define search function that you pass an array and a search string to
function search($needle,$haystack){
// loop over each passed in array element
foreach($haystack as $v){
// if there is a match at the first position
if(strpos($v,$needle) === 0)
// return the current array element
return $v;
}
// otherwise retur false if not found
return false;
}
// test the function
echo search("Would",$arr);
?>
are the indices important ? why not ..
$arr = array(
'Title' => array(11, 11),
'Would' => array(22, 22),
'Post' => array(55, 55),
'Ask' => array(66,66)
);
$send = "Title"; // for example
$result = $arr[$send];
How about using something like, so you don't loop trough entire array:
$array = array( "Title,11,11", "Would,22,22", "Post,55,55", "Ask,66,66" );
$key = my_array_search('Would', $array);
$getvalues = explode(",", $array[$key]);
function my_array_search($needle = null, $haystack_array = null, $skip = 0)
{
if($needle == null || $haystack_array == null)
die('$needle and $haystack_array are mandatory for function my_array_search()');
foreach($haystack_array as $key => $eval)
{
if($skip != 0)$eval = substr($eval, $skip);
if(stristr($eval, $needle) !== false) return $key;
}
return false;
}
I have an associative array in the form key => value where key is a numerical value, however it is not a sequential numerical value. The key is actually an ID number and the value is a count. This is fine for most instances, however I want a function that gets the human-readable name of the array and uses that for the key, without changing the value.
I didn't see a function that does this, but I'm assuming I need to provide the old key and new key (both of which I have) and transform the array. Is there an efficient way of doing this?
$arr[$newkey] = $arr[$oldkey];
unset($arr[$oldkey]);
The way you would do this and preserve the ordering of the array is by putting the array keys into a separate array, find and replace the key in that array and then combine it back with the values.
Here is a function that does just that:
function change_key( $array, $old_key, $new_key ) {
if( ! array_key_exists( $old_key, $array ) )
return $array;
$keys = array_keys( $array );
$keys[ array_search( $old_key, $keys ) ] = $new_key;
return array_combine( $keys, $array );
}
if your array is built from a database query, you can change the key directly from the mysql statement:
instead of
"select ´id´ from ´tablename´..."
use something like:
"select ´id´ **as NEWNAME** from ´tablename´..."
The answer from KernelM is nice, but in order to avoid the issue raised by Greg in the comment (conflicting keys), using a new array would be safer
$newarr[$newkey] = $oldarr[$oldkey];
$oldarr=$newarr;
unset($newarr);
$array = [
'old1' => 1
'old2' => 2
];
$renameMap = [
'old1' => 'new1',
'old2' => 'new2'
];
$array = array_combine(array_map(function($el) use ($renameMap) {
return $renameMap[$el];
}, array_keys($array)), array_values($array));
/*
$array = [
'new1' => 1
'new2' => 2
];
*/
You could use a second associative array that maps human readable names to the id's. That would also provide a Many to 1 relationship. Then do something like this:
echo 'Widgets: ' . $data[$humanreadbleMapping['Widgets']];
If you want also the position of the new array key to be the same as the old one you can do this:
function change_array_key( $array, $old_key, $new_key) {
if(!is_array($array)){ print 'You must enter a array as a haystack!'; exit; }
if(!array_key_exists($old_key, $array)){
return $array;
}
$key_pos = array_search($old_key, array_keys($array));
$arr_before = array_slice($array, 0, $key_pos);
$arr_after = array_slice($array, $key_pos + 1);
$arr_renamed = array($new_key => $array[$old_key]);
return $arr_before + $arr_renamed + $arr_after;
}
Simple benchmark comparison of both solution.
Solution 1 Copy and remove (order lost, but way faster) https://stackoverflow.com/a/240676/1617857
<?php
$array = ['test' => 'value', ['etc...']];
$array['test2'] = $array['test'];
unset($array['test']);
Solution 2 Rename the key https://stackoverflow.com/a/21299719/1617857
<?php
$array = ['test' => 'value', ['etc...']];
$keys = array_keys( $array );
$keys[array_search('test', $keys, true)] = 'test2';
array_combine( $keys, $array );
Benchmark:
<?php
$array = ['test' => 'value', ['etc...']];
for ($i =0; $i < 100000000; $i++){
// Solution 1
}
for ($i =0; $i < 100000000; $i++){
// Solution 2
}
Results:
php solution1.php 6.33s user 0.02s system 99% cpu 6.356 total
php solution1.php 6.37s user 0.01s system 99% cpu 6.390 total
php solution2.php 12.14s user 0.01s system 99% cpu 12.164 total
php solution2.php 12.57s user 0.03s system 99% cpu 12.612 total
If your array is recursive you can use this function:
test this data:
$datos = array
(
'0' => array
(
'no' => 1,
'id_maquina' => 1,
'id_transaccion' => 1276316093,
'ultimo_cambio' => 'asdfsaf',
'fecha_ultimo_mantenimiento' => 1275804000,
'mecanico_ultimo_mantenimiento' =>'asdfas',
'fecha_ultima_reparacion' => 1275804000,
'mecanico_ultima_reparacion' => 'sadfasf',
'fecha_siguiente_mantenimiento' => 1275804000,
'fecha_ultima_falla' => 0,
'total_fallas' => 0,
),
'1' => array
(
'no' => 2,
'id_maquina' => 2,
'id_transaccion' => 1276494575,
'ultimo_cambio' => 'xx',
'fecha_ultimo_mantenimiento' => 1275372000,
'mecanico_ultimo_mantenimiento' => 'xx',
'fecha_ultima_reparacion' => 1275458400,
'mecanico_ultima_reparacion' => 'xx',
'fecha_siguiente_mantenimiento' => 1275372000,
'fecha_ultima_falla' => 0,
'total_fallas' => 0,
)
);
here is the function:
function changekeyname($array, $newkey, $oldkey)
{
foreach ($array as $key => $value)
{
if (is_array($value))
$array[$key] = changekeyname($value,$newkey,$oldkey);
else
{
$array[$newkey] = $array[$oldkey];
}
}
unset($array[$oldkey]);
return $array;
}
I like KernelM's solution, but I needed something that would handle potential key conflicts (where a new key may match an existing key). Here is what I came up with:
function swapKeys( &$arr, $origKey, $newKey, &$pendingKeys ) {
if( !isset( $arr[$newKey] ) ) {
$arr[$newKey] = $arr[$origKey];
unset( $arr[$origKey] );
if( isset( $pendingKeys[$origKey] ) ) {
// recursion to handle conflicting keys with conflicting keys
swapKeys( $arr, $pendingKeys[$origKey], $origKey, $pendingKeys );
unset( $pendingKeys[$origKey] );
}
} elseif( $newKey != $origKey ) {
$pendingKeys[$newKey] = $origKey;
}
}
You can then cycle through an array like this:
$myArray = array( '1970-01-01 00:00:01', '1970-01-01 00:01:00' );
$pendingKeys = array();
foreach( $myArray as $key => $myArrayValue ) {
// NOTE: strtotime( '1970-01-01 00:00:01' ) = 1 (a conflicting key)
$timestamp = strtotime( $myArrayValue );
swapKeys( $myArray, $key, $timestamp, $pendingKeys );
}
// RESULT: $myArray == array( 1=>'1970-01-01 00:00:01', 60=>'1970-01-01 00:01:00' )
Here is a helper function to achieve that:
/**
* Helper function to rename array keys.
*/
function _rename_arr_key($oldkey, $newkey, array &$arr) {
if (array_key_exists($oldkey, $arr)) {
$arr[$newkey] = $arr[$oldkey];
unset($arr[$oldkey]);
return TRUE;
} else {
return FALSE;
}
}
pretty based on #KernelM answer.
Usage:
_rename_arr_key('oldkey', 'newkey', $my_array);
It will return true on successful rename, otherwise false.
this code will help to change the oldkey to new one
$i = 0;
$keys_array=array("0"=>"one","1"=>"two");
$keys = array_keys($keys_array);
for($i=0;$i<count($keys);$i++) {
$keys_array[$keys_array[$i]]=$keys_array[$i];
unset($keys_array[$i]);
}
print_r($keys_array);
display like
$keys_array=array("one"=>"one","two"=>"two");
Easy stuff:
this function will accept the target $hash and $replacements is also a hash containing newkey=>oldkey associations.
This function will preserve original order, but could be problematic for very large (like above 10k records) arrays regarding performance & memory.
function keyRename(array $hash, array $replacements) {
$new=array();
foreach($hash as $k=>$v)
{
if($ok=array_search($k,$replacements))
$k=$ok;
$new[$k]=$v;
}
return $new;
}
this alternative function would do the same, with far better performance & memory usage, at the cost of losing original order (which should not be a problem since it is hashtable!)
function keyRename(array $hash, array $replacements) {
foreach($hash as $k=>$v)
if($ok=array_search($k,$replacements))
{
$hash[$ok]=$v;
unset($hash[$k]);
}
return $hash;
}
This page has been peppered with a wide interpretation of what is required because there is no minimal, verifiable example in the question body. Some answers are merely trying to solve the "title" without bothering to understand the question requirements.
The key is actually an ID number and the value is a count. This is
fine for most instances, however I want a function that gets the
human-readable name of the array and uses that for the key, without
changing the value.
PHP keys cannot be changed but they can be replaced -- this is why so many answers are advising the use of array_search() (a relatively poor performer) and unset().
Ultimately, you want to create a new array with names as keys relating to the original count. This is most efficiently done via a lookup array because searching for keys will always outperform searching for values.
Code: (Demo)
$idCounts = [
3 => 15,
7 => 12,
8 => 10,
9 => 4
];
$idNames = [
1 => 'Steve',
2 => 'Georgia',
3 => 'Elon',
4 => 'Fiona',
5 => 'Tim',
6 => 'Petra',
7 => 'Quentin',
8 => 'Raymond',
9 => 'Barb'
];
$result = [];
foreach ($idCounts as $id => $count) {
if (isset($idNames[$id])) {
$result[$idNames[$id]] = $count;
}
}
var_export($result);
Output:
array (
'Elon' => 15,
'Quentin' => 12,
'Raymond' => 10,
'Barb' => 4,
)
This technique maintains the original array order (in case the sorting matters), doesn't do any unnecessary iterating, and will be very swift because of isset().
If you want to replace several keys at once (preserving order):
/**
* Rename keys of an array
* #param array $array (asoc)
* #param array $replacement_keys (indexed)
* #return array
*/
function rename_keys($array, $replacement_keys) {
return array_combine($replacement_keys, array_values($array));
}
Usage:
$myarr = array("a" => 22, "b" => 144, "c" => 43);
$newkeys = array("x","y","z");
print_r(rename_keys($myarr, $newkeys));
//must return: array("x" => 22, "y" => 144, "z" => 43);
You can use this function based on array_walk:
function mapToIDs($array, $id_field_name = 'id')
{
$result = [];
array_walk($array,
function(&$value, $key) use (&$result, $id_field_name)
{
$result[$value[$id_field_name]] = $value;
}
);
return $result;
}
$arr = [0 => ['id' => 'one', 'fruit' => 'apple'], 1 => ['id' => 'two', 'fruit' => 'banana']];
print_r($arr);
print_r(mapToIDs($arr));
It gives:
Array(
[0] => Array(
[id] => one
[fruit] => apple
)
[1] => Array(
[id] => two
[fruit] => banana
)
)
Array(
[one] => Array(
[id] => one
[fruit] => apple
)
[two] => Array(
[id] => two
[fruit] => banana
)
)
This basic function handles swapping array keys and keeping the array in the original order...
public function keySwap(array $resource, array $keys)
{
$newResource = [];
foreach($resource as $k => $r){
if(array_key_exists($k,$keys)){
$newResource[$keys[$k]] = $r;
}else{
$newResource[$k] = $r;
}
}
return $newResource;
}
You could then loop through and swap all 'a' keys with 'z' for example...
$inputs = [
0 => ['a'=>'1','b'=>'2'],
1 => ['a'=>'3','b'=>'4']
]
$keySwap = ['a'=>'z'];
foreach($inputs as $k=>$i){
$inputs[$k] = $this->keySwap($i,$keySwap);
}
This function will rename an array key, keeping its position, by combining with index searching.
function renameArrKey($arr, $oldKey, $newKey){
if(!isset($arr[$oldKey])) return $arr; // Failsafe
$keys = array_keys($arr);
$keys[array_search($oldKey, $keys)] = $newKey;
$newArr = array_combine($keys, $arr);
return $newArr;
}
Usage:
$arr = renameArrKey($arr, 'old_key', 'new_key');
this works for renaming the first key:
$a = ['catine' => 'cat', 'canine' => 'dog'];
$tmpa['feline'] = $a['catine'];
unset($a['catine']);
$a = $tmpa + $a;
then, print_r($a) renders a repaired in-order array:
Array
(
[feline] => cat
[canine] => dog
)
this works for renaming an arbitrary key:
$a = ['canine' => 'dog', 'catine' => 'cat', 'porcine' => 'pig']
$af = array_flip($a)
$af['cat'] = 'feline';
$a = array_flip($af)
print_r($a)
Array
(
[canine] => dog
[feline] => cat
[porcine] => pig
)
a generalized function:
function renameKey($oldkey, $newkey, $array) {
$val = $array[$oldkey];
$tmp_A = array_flip($array);
$tmp_A[$val] = $newkey;
return array_flip($tmp_A);
}
There is an alternative way to change the key of an array element when working with a full array - without changing the order of the array.
It's simply to copy the array into a new array.
For instance, I was working with a mixed, multi-dimensional array that contained indexed and associative keys - and I wanted to replace the integer keys with their values, without breaking the order.
I did so by switching key/value for all numeric array entries - here: ['0'=>'foo']. Note that the order is intact.
<?php
$arr = [
'foo',
'bar'=>'alfa',
'baz'=>['a'=>'hello', 'b'=>'world'],
];
foreach($arr as $k=>$v) {
$kk = is_numeric($k) ? $v : $k;
$vv = is_numeric($k) ? null : $v;
$arr2[$kk] = $vv;
}
print_r($arr2);
Output:
Array (
[foo] =>
[bar] => alfa
[baz] => Array (
[a] => hello
[b] => world
)
)
best way is using reference, and not using unset (which make another step to clean memory)
$tab = ['two' => [] ];
solution:
$tab['newname'] = & $tab['two'];
you have one original and one reference with new name.
or if you don't want have two names in one value is good make another tab and foreach on reference
foreach($tab as $key=> & $value) {
if($key=='two') {
$newtab["newname"] = & $tab[$key];
} else {
$newtab[$key] = & $tab[$key];
}
}
Iterration is better on keys than clone all array, and cleaning old array if you have long data like 100 rows +++ etc..
One which preservers ordering that's simple to understand:
function rename_array_key(array $array, $old_key, $new_key) {
if (!array_key_exists($old_key, $array)) {
return $array;
}
$new_array = [];
foreach ($array as $key => $value) {
$new_key = $old_key === $key
? $new_key
: $key;
$new_array[$new_key] = $value;
}
return $new_array;
}
Here is an experiment (test)
Initial array (keys like 0,1,2)
$some_array[] = '6110';//
$some_array[] = '6111';//
$some_array[] = '6210';//
I must change key names to for example human_readable15, human_readable16, human_readable17
Something similar as already posted. During each loop i set necessary key name and remove corresponding key from the initial array.
For example, i inserted into mysql $some_array got lastInsertId and i need to send key-value pair back to jquery.
$first_id_of_inserted = 7;//lastInsertId
$last_loop_for_some_array = count($some_array);
for ($current_loop = 0; $current_loop < $last_loop_for_some_array ; $current_loop++) {
$some_array['human_readable'.($first_id_of_inserted + $current_loop)] = $some_array[$current_loop];//add new key for intial array
unset( $some_array[$current_loop] );//remove already renamed key from array
}
And here is the new array with renamed keys
echo '<pre>', print_r($some_array, true), '</pre>$some_array in '. basename(__FILE__, '.php'). '.php <br/>';
If instead of human_readable15, human_readable16, human_readable17 need something other. Then could create something like this
$arr_with_key_names[] = 'human_readable';
$arr_with_key_names[] = 'something_another';
$arr_with_key_names[] = 'and_something_else';
for ($current_loop = 0; $current_loop < $last_loop_for_some_array ; $current_loop++) {
$some_array[$arr_with_key_names[$current_loop]] = $some_array[$current_loop];//add new key for intial array
unset( $some_array[$current_loop] );//remove already renamed key from array
}
Hmm, I'm not test before, but I think this code working
function replace_array_key($data) {
$mapping = [
'old_key_1' => 'new_key_1',
'old_key_2' => 'new_key_2',
];
$data = json_encode($data);
foreach ($mapping as $needed => $replace) {
$data = str_replace('"'.$needed.'":', '"'.$replace.'":', $data);
}
return json_decode($data, true);
}
You can write simple function that applies the callback to the keys of the given array. Similar to array_map
<?php
function array_map_keys(callable $callback, array $array) {
return array_merge([], ...array_map(
function ($key, $value) use ($callback) { return [$callback($key) => $value]; },
array_keys($array),
$array
));
}
$array = ['a' => 1, 'b' => 'test', 'c' => ['x' => 1, 'y' => 2]];
$newArray = array_map_keys(function($key) { return 'new' . ucfirst($key); }, $array);
echo json_encode($array); // {"a":1,"b":"test","c":{"x":1,"y":2}}
echo json_encode($newArray); // {"newA":1,"newB":"test","newC":{"x":1,"y":2}}
Here is a gist https://gist.github.com/vardius/650367e15abfb58bcd72ca47eff096ca#file-array_map_keys-php.