PHP: Find last occurence of string in array - php

I need to find the last found element of a specific value from an array. I giving an example in php of what I'm actually seeking for.
$Data = array(
'0' => 'car',
'1' => 'bike',
'2' => 'bus',
'3' => 'bike',
'4' => 'boat'
);
$key = array_search('bike', $Data) // it returns $key = 1 as result which the first element matched inside the array.
I want $key = 3 which is the last matched element.
Any suggestion appreciated.

PHP code demo
<?php
ini_set("display_errors", 1);
$Data = array(
'0' => 'car',
'1' => 'bike',
'2' => 'bus',
'3' => 'bike',
'4' => 'boat'
);
$toSearch="bike";
$index=null;
while($key=array_search($toSearch, $Data))
{
$index=$key;
unset($Data[$key]);
}
echo $index;

Here is the more simple and highly performace way. For it only calculate once, you can access it many time. The live demo.
$data = array_flip($Data);
echo $data['bike'];
after the flip, only keep the last element of the same elements. Here is the print_r($data)
Array
(
[car] => 0
[bike] => 3
[bus] => 2
[boat] => 4
)

We can use array_reverse to reverse array.
$key = array_search('bike', array_reverse($Data,true));
It will return 3.

you can use krsort to sort the array by key.
krsort($Data);
$key = array_search('bike', $Data);
echo $key;
Working example: https://3v4l.org/fYOgN

For this I am created one function it is very easy to use. You can pass only array and parameters.
function text_to_id($value, $arr_master) {
$id_selected = 0;
$search_array = $arr_master;
if (in_array($value, $search_array)) {
$id_selected = array_search($value, $search_array);
// pr($id_selected);exit;
}
if (!$id_selected) {
foreach ($search_array as $f_key => $f_value) {
if (is_array($f_value)) {
if (in_array($value, $f_value)) {
$id_selected = $f_key;
break;
}
} else if ($value == $f_value) {
$id_selected = $f_key;
break;
}
else;
}
}
return $id_selected;
}
this function use like this
$variable = text_to_id('bike', $your_array);

Related

How to get a multidimensional array's name?

I'm trying to get the name of an array once I have found a specific value.
Specifically I'm looking to get the highest and lowest values within my array for a certain key, once I have those values I then need to get the name of the array holding those values.
My array looks like this -
Array
(
[123456] => Array
(
[value1] => 0.524
[value2] => 0.898
[value3] => -6.543
)
[246810] => Array
(
[value1] => 0.579
[value2] => 0.989
[value3] => -5.035
)
I have gotten the max value using this code -
max(array_column($statsArr, 'value1'));
This, correctly, gives me the value "0.579". I now need to get the value of the array holding this information so in this case I also want to get the value "246810". I don't know how to do this though, any help would be appreciated!
Iterate over your array with a simple foreach and save required key:
$max = 0;
$founded_key = false;
foreach ($array as $key => $value) {
if ($max < $value['value1']) {
$max = $value['value1'];
$founded_key = $key;
}
}
echo $founded_key, ' - ', $max;
For these kinds of problems I like using array_reduce. max is itself an array reduce operation which takes an array and returns a single value, PHP just offers it out of the box as convenience since it's a very common operation.
Here's an example code:
$array = array(
123456 => array(
'value1' => 0.524,
'value2' => 0.898,
'value3' => -6.543
),
246810 => array(
'value1' => 0.579,
'value2' => 0.989,
'value3' => -5.035
)
);
$maxKey = array_reduce(array_keys($array), function ($carry, $key) use ($array) {
if ($carry === null) {
return $key;
}
return $array[$key]['value1'] > $array[$carry]['value1'] ? $key : $carry;
}, null);
$maxValue = $array[$maxKey]['value1'];
Working example: http://sandbox.onlinephpfunctions.com/code/ecd400ffec91a6436c2fb5ee0410658e22772d4b
function getMax($array, $field) {
$maxValue = null;
$maxKey = null;
foreach($array as $key => $content) {
if (is_null($maxValue) || $content[$field] > $maxValue) {
$maxValue = $content[$field];
$maxKey = $key;
}
}
return [$maxValue, $maxKey];
}
You can search for the maximum value in the array_column.
I first prepare the array_column with correct keys by combining it, then find the max like you do.
Then we can array_search the value.
$value1 = array_combine(array_keys($statsArr), array_column($statsArr, 'value1'));
$max = max($value1);
echo $max . PHP_EOL;
$array = $statsArr[array_search($max, $value1)];
var_dump($array);
https://3v4l.org/Q9gOX
Alternatively you can array_values the $statsArr to make it 0 indexed just like the array_column.
$value1 = array_column($statsArr, 'value1');
$max = max($value1);
echo $max . PHP_EOL;
$array = array_values($statsArr)[array_search($max, $value1)];
var_dump($array);

Search in a multidimensional assoc array

I have an array, looking like this:
[lund] => Array
(
[69] => foo
)
[berlin] => Array
(
[138] => foox2
)
[tokyo] => Array
(
[180] => foox2
[109] => Big entrance
[73] => foo
)
The thing is that there were duplicate keys, so I re-arranged them so I can search more specifically, I thought.
Previously I could just
$key = array_search('foo', $array);
to get the key but now I don't know how.
Question: I need key for value foo, from tokyo. How do I do that?
You can get all keys and value of foo by using this:
foreach ($array as $key => $value) {
$newArr[$key] = array_search('foo', $value);
}
print_r(array_filter($newArr));
Result is:
Array
(
[lund] => 69
[tokyo] => 109
)
If you don't mind about the hard code than you can use this:
array_search('foo', $array['tokyo']);
It just a simple example, you can modify it as per your requirement.
Try this
$a = array(
"land"=> array("69"=>"foo"),
"land1"=> array("138"=>"foo1"),
"land2"=> array('180' => 'foox2',
'109' => 'Big entrance',
'73' => 'foo'),
);
//print_r($a);
$reply = search_in_array($a, "foo");
print_r($reply);
function search_in_array($a, $search)
{
$result = array();
foreach($a as $key1 => $array ) {
foreach($array as $k => $value) {
if($value == "$search") {
array_push($result,"{$key1}=>{$k}");
breck;
}
}
}
return $result;
}
This function will return the key or null if the search value is not found.
function search($searchKey, $searchValue, $searchArr)
{
foreach ($searchArr as $key => $value) {
if ($key == $searchKey && in_array($searchValue, $value)) {
$results = array_search($searchValue, $value);
}
}
return isset($results) ? $results : null;
}
// var_dump(search('tokyo', 'foo', $array));
Since Question: I need key for value foo, from tokyo. How do i do that?
$key = array_search('foo', $array['tokyo']);
As a function:
function getKey($keyword, $city, $array) {
return array_search($keyword, $array[$city]);
}
// PS. Might be a good idea to wrap this array in an object and make getKey an object method.
If you want to get all cities (for example to loop through them):
$cities = array_keys($array);
I created solution using array iterator. Have a look on below solution:
$array = array(
'lund' => array
(
'69' => 'foo'
),
'berlin' => array
(
'138' => 'foox2'
),
'tokyo' => array
(
'180' => 'foox2',
'109' => 'Big entrance',
'73' => 'foo'
)
);
$main_key = 'tokyo'; //key of array
$search_value = 'foo'; //value which need to be search
$iterator = new RecursiveIteratorIterator(new RecursiveArrayIterator($array));
foreach ($iterator as $key => $value) {
$keys = array();
if ($value == $search_value) {
$keys[] = $key;
for ($i = $iterator->getDepth() - 1; $i >= 0; $i--) {
$keys[] = $iterator->getSubIterator($i)->key();
}
$key_paths = array_reverse($keys);
if(in_array($main_key, $key_paths) !== false) {
echo "'{$key}' have '{$value}' value which traverse path is: " . implode(' -> ', $key_paths) . '<br>';
}
}
}
you can change value of $main_key and $serch_value according to your parameter. hope this will help you.
<?php
$lund = [
'69' => 'foo'
];
$berlin = [
'138' => 'foox2'
];
$tokyo = [
'180' => 'foox2',
'109' => 'Big entrance',
'73' => 'foo'
];
$array = [
$lund,
$berlin,
$tokyo
];
echo $array[2]['180']; // outputs 'foox2' from $tokyo array
?>
If you want to get key by specific key and value then your code should be:
function search_array($array, $key, $value)
{
if(is_array($array[$key])) {
return array_search($value, $array[$key]);
}
}
echo search_array($arr, 'tokyo', 'foo');
try this:
<?php
error_reporting(E_ALL | E_STRICT);
ini_set('display_errors', 'On');
$array=array("lund" => array
(
69 => "foo"
),
"berlin" => array
(
138 => "foox2"
),
"tokyo" => array
(
180 => "foox2",
109 => "Big entrance",
73 => "foo"
));
function search($array, $arrkey1, $arrvalue2){
foreach($array as $arrkey=>$arrvalue){
if($arrkey == $arrkey1){
foreach($arrvalue as $arrkey=>$arrvalue){
if(preg_match("/$arrvalue/i",$arrvalue2))
return $arrkey;
}
}
}
}
$result=search($array, "tokyo", "foo"); //$array=array; tokyo="inside array to check"; foo="value" to check
echo $result;
You need to loop through array, since its 2 dimensional in this case. And then find corresponding value.
foreach($arr as $key1 => $key2 ) {
foreach($key2 as $k => $value) {
if($value == "foo") {
echo "{$k} => {$value}";
}
}
}
This example match key with $value, but you can do match with $k also, which in this case is $key2.

PHP Find a value in a key and get the value of another key in a multi-dimentional array

Might be a newbie question but I've been trying to figure this problem and it's doing my head in.
I have the following array :
[0] => Array
(
[provisionalBookingRoomID] => 1
[totalSpecificRoomCount] => 2
)
[1] => Array
(
[provisionalBookingRoomID] => 2
[totalSpecificRoomCount] => 5
)
I need a php function that searches through the array for the value of 'provisionalBookingRoomID' and returns the value of 'totalSpecificRoomCount'
basically something like the following
getProvisionalTotalRoomsCount($currentRoom, $arrayOfRooms);
// getProvisionalTotalRoomsCount('1', $arrayOfRooms) should return 2;
Any ideas?
Check this:
getProvisionalTotalRoomsCount($currentRoom, $arrayOfRooms){
foreach($arrayOfRooms as $key=>$value){
if($value['provisionalBookingRoomID'] == $currentRoom){
return $value['totalSpecificRoomCount'];
}
}
}
For anyone looking for a generic function :
function findValueInArray($array, $searchValue, $searchKey, $requiredKeyValue) {
foreach($array as $key=>$value){
if($value[$searchKey] == $searchValue){
return $value[$requiredKeyValue];
}
}
}
// Usage : findValueInArray($provisionalBookedRoomsArray, '1', 'provisionalBookingRoomID', 'totalSpecificRoomCount');
If you are likely to work with more than one value, you could build a new array with a 1->1 map for those attributes.
<?php
$items = array(
array(
'name' => 'Foo',
'age' => 23
),
array(
'name' => 'Bar',
'age' => 47
)
);
// Php 7
$name_ages = array_column($items, 'name', 'age');
echo $name_ages['Foo']; // Output 23
// Earlier versions:
$name_ages = array();
foreach($items as $value)
{
$name_ages[$value['name']] = $value['age'];
}
echo $name_ages['Foo']; // Output 23
$value = 0;
$array = array(array("provisionalBookingRoomID"=>1,"totalSpecificRoomCount"=>2),array("provisionalBookingRoomID"=>2,"totalSpecificRoomCount"=>5));
array_map(
function($arr) use (&$value) {
if($arr['provisionalBookingRoomID']==1) {
$value = $arr['totalSpecificRoomCount'];
}
},$array
);
echo $value;

How to compare and filter 2 arrays

first array like this
$zones_array1 = array();
$zones_array1[] = array('id' => 'Alabama', 'text' => 'Alabama');
$zones_array1[] = array('id' => 'Alaska', 'text' => 'Alaska');
$zones_array1[] = array('id' => 'Arizona', 'text' => 'Arizona');
$zones_array1[] = array('id' => 'Arkansas', 'text' => 'Arkansas');
second array like this
$zones_array2 = array();
$zones_array2[] = array('id' => 'Alaska', 'text' => 'Alaska');
$zones_array2[] = array('id' => 'Arizona', 'text' => 'Arizona');
i want filter these two array and i want final result as array like this
first array like this
$zones_array3 = array();
$zones_array3[] = array('id' => 'Alabama', 'text' => 'Alabama');
$zones_array3[] = array('id' => 'Arkansas', 'text' => 'Arkansas');
please help me
You can use php 'in_array' to check weather an element exists inside other array or not. In you case the array is multidimensional so stored all the id's inside a newly created array and then compared the given array with that.
$check_array = array();
foreach ($zones_array1 as $arr1){
$check_array[] = $arr1['id'];
}
$zones_array3 = array();
foreach ($zones_array2 as $arr2){
if (!in_array($arr2['id'], $check_array))
{
$zones_array3[] = $arr2;
}
}
echo '<pre>';
print_r($zones_array3);
Simply try:
function udiffCompare($a, $b)
{
return $a['id'] == $b['id'] ? 0 : -1;
}
$arrdiff = array_udiff($zones_array1, $zones_array2, 'udiffCompare');
echo '<pre>';
print_r($arrdiff);
array_udiff() compares each element of the first array-argument against all the elements of the second array-argument using the provided callback function. If the callback returns zero for any of the comparisons then the element of the array in the first argument will not be present in the returned array of the function.
You will try it :
function unique_multidim_array($array, $key){
$temp_array = array();
$i = 0;
$key_array = array();
foreach($array as $val){
if(!in_array($val[$key],$key_array)){
$key_array[$i] = $val[$key];
$temp_array[$i] = $val;
}
$i++;
}
return $temp_array;
}
$zones_array1 = array_merge($zones_array2, $zones_array3);
$zones_array1 = unique_multidim_array($zones_array1, 'id');
print_r($zones_array1);
Please try this
array_push($zones_array1,$zones_array2);
print_r(array_unique($zones_array1));
I am not sure.

Replace keys in an array based on another lookup/mapping array

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.

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