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);
I have an array that looks something like this:
$array = array( [0] => FILE-F01-E1-S01.pdf
[1] => FILE-F01-E1-S02.pdf
[2] => FILE-F01-E1-S03.pdf
[3] => FILE-F01-E1-S04.pdf
[4] => FILE-F01-E1-S05.pdf
[5] => FILE-F02-E1-S01.pdf
[6] => FILE-F02-E1-S02.pdf
[7] => FILE-F02-E1-S03.pdf );
Basically, I need to look at the first file and then get all the other files that have the same beginning ('FILE-F01-E1', for example) and put them into an array. I don't need to do anything with the other ones at this point.
I've been trying to use a foreach loop finding the previous value to do this, but am not having any luck.
Like this:
$previousFile = null;
foreach($array as $file)
{
if(substr_replace($previousFile, "", -8) == substr_replace($file, "", -8))
{
$secondArray[] = $file;
}
$previousFile = $file;
}
So then $secondArray would look like this:
Array ( [0] => FILE-F01-E1-S01.pdf [1] => FILE-F01-E1-S02.pdf
[2] => FILE-F01-E1-S03.pdf [3] => FILE-F01-E1-S04.pdf
[4] => FILE-F01-E1-S05.pdf)
As my result.
Thank you!
You can use array_filter combined with strpos:
$result = array_filter($array, function($filename) {
return strpos($filename, 'FILE-F01-E1') === 0;
});
Are you sure this will be the naming format? That is crucial information to have to construct a regexp or something to check for being a substring of the following strings.
If we can assume this and that the "base" name is always at index 0 then you could do something like.
<?php
$myArr = [
'FILE-F01-E1-S01.pdf',
'FILE-F01-E1-S02.pdf',
'FILE-F01-E1-S03.pdf',
'FILE-F01-E1-S04.pdf',
'FILE-F01-E1-S05.pdf',
'FILE-F02-E1-S01.pdf',
'FILE-F02-E1-S02.pdf',
'FILE-F02-E1-S03.pdf'
];
$baseName = '';
$allSimilarNames = [];
foreach($myArr as $index => &$name) {
if($index == 0) {
$baseName = substr($name, 0, strrpos($name, '-'));
$allSimilarNames[] = $name;
}
else {
if(strpos($name, $baseName) === 0) {
$allSimilarNames[] = $name;
}
}
}
var_dump($allSimilarNames);
This will
Check at index one to get the base name to compare against
Loop all items in the array and match all items, no matter where in the array they are, that are similar according to your naming convention
So if you next time have an array that is
$myArr = [
'FILE-F02-E1-S01.pdf',
'FILE-F01-E1-S01.pdf',
'FILE-F01-E1-S02.pdf',
'FILE-F01-E1-S03.pdf',
'FILE-F01-E1-S04.pdf',
'FILE-F01-E1-S05.pdf',
'FILE-F02-E1-S02.pdf',
'FILE-F02-E1-S03.pdf'
];
this will return all the items that match FILE-F02-E1*.
You could also make a small function of it for easier use and not have to rely on the element at index 0 having to be the "base" name.
<?php
function findMatches($baseName, &$names) {
$matches = [];
$baseName = substr($baseName, 0, strrpos($baseName, '-'));
foreach($names as &$name) {
if(strpos($name, $baseName) === 0) {
$matches[] = $name;
}
}
return $matches;
}
$myArr = [
'FILE-F01-E1-S01.pdf',
'FILE-F01-E1-S02.pdf',
'FILE-F01-E1-S03.pdf',
'FILE-F01-E1-S04.pdf',
'FILE-F01-E1-S05.pdf',
'FILE-F02-E1-S01.pdf',
'FILE-F02-E1-S02.pdf',
'FILE-F02-E1-S03.pdf'
];
$allSimilarNames = findMatches('FILE-F01-E1-S01.pdf', $myArr);
var_dump($allSimilarNames);
Run a simple foreach with strpos() which looks for an occurrence of a string within a string.
$results = array();
foreach($array as $item){
if (strpos($item, 'FILE-F01-E1') === 0) {
array_push($results, $item);
}
}
You could get the first item from the array and use explode and implode to get the part from the filename without the last hyphen and the content after that.
Then use array_filter and use substr using 0 as the start position and the length of the $fileBeginning as the length to check if the string starts with FILE-F01-E1:
$array = [
'FILE-F01-E1-S01.pdf',
'FILE-F01-E1-S02.pdf',
'FILE-F01-E1-S03.pdf',
'FILE-F01-E1-S04.pdf',
'FILE-F01-E1-S05.pdf',
'FILE-F02-E1-S01.pdf',
'FILE-F02-E1-S02.pdf',
'FILE-F02-E1-S03.pdf',
"TESTFILE-F01-E1-S03.pdf"
];
$parts = explode('-', $array[0]);
array_pop($parts);
$fileBeginning = implode('-', $parts);
$secondArray = array_filter($array, function ($x) use ($fileBeginning) {
return substr($x, 0, strlen($fileBeginning)) === $fileBeginning;
});
print_r($secondArray);
Result
Array
(
[0] => FILE-F01-E1-S01.pdf
[1] => FILE-F01-E1-S02.pdf
[2] => FILE-F01-E1-S03.pdf
[3] => FILE-F01-E1-S04.pdf
[4] => FILE-F01-E1-S05.pdf
)
Demo
OK, I already got this question in stackoverflow but sadly it's in javascript - Javascript - sort array based on another array
and I want it in PHP
$data = array(
"item1"=>"1",
"item2"=>"3",
"item3"=>"5",
"item4"=>"2",
"item5"=>"4"
);
to match the arrangement of this array:
sortingArr = array("5","4","3","2","1");
and the output I'm looking for:
$data = array(
"item3"=>"5",
"item5"=>"4",
"item2"=>"3",
"item4"=>"2",
"item1"=>"1"
);
Any idea how this can be done?
Thanks.
For a detailed answer, why array_multisort does not match your needs, view this answer, please:
PHP array_multisort not sorting my multidimensional array as expected
In short: You want to sort an array based on a predefined order. The Answer is also given over there, but i copied one solution to this answer, too:
Use usort and array_flip, so you be able to turn your indexing array (ValueByPosition) into a PositionByValue Array.
$data = array(
"item1"=>"1",
"item2"=>"3",
"item3"=>"5",
"item4"=>"2",
"item5"=>"4"
);
usort($data, "sortByPredefinedOrder");
function sortByPredefinedOrder($leftItem, $rightItem){
$order = array("5","4","3","2","1");
$flipped = array_flip($order);
$leftPos = $flipped[$leftItem];
$rightPos = $flipped[$rightItem];
return $leftPos >= $rightPos;
}
print_r($data);
// usort: Array ( [0] => 5 [1] => 4 [2] => 3 [3] => 2 [4] => 1 )
// uasort: Array ( [item3] => 5 [item5] => 4 [item2] => 3 [item4] => 2 [item1] => 1 )
However this would require you to predict all possible items inside the predefined order array, or thread other items in an appropriate way.
If you want to maintain the assoc keys, use uasort instead of usort.
Pretty simple ?
$data = array(
"item1"=>"1",
"item2"=>"3",
"item3"=>"5",
"item4"=>"2",
"item5"=>"4"
);
$sortingArr = array("5","4","3","2","1");
$result = array(); // result array
foreach($sortingArr as $val){ // loop
$result[array_search($val, $data)] = $val; // adding values
}
print_r($result); // print results
Output:
Array
(
[item3] => 5
[item5] => 4
[item2] => 3
[item4] => 2
[item1] => 1
)
using usort() the right way i think
Sort an array by values using a user-defined comparison function
you can do as follow:
$data = array(
"item1"=>"1",
"item2"=>"3",
"item3"=>"5",
"item4"=>"2",
"item5"=>"4"
);
$sortingArr = array("5","4","3","2","1");
$keys = array_flip($sortingArr);
usort($data, function ($a, $b) use ($keys) {
return $keys[$a] > $keys[$b] ? 1 : -1;
});
print_r($data);
// Output
// Array ( [0] => 5 [1] => 4 [2] => 3 [3] => 2 [4] => 1 )
live example: https://3v4l.org/75cnu
Look at my following snippet to sort your array based on another array:
$res_arr = array();
for ($i = 0; $i < count($sortingArr); $i++) {
for ($j = 0; $j < count($data); $j++) {
if($data[$j] == $sortingArr[$i]) {
$res_arr[] = $data[$j];
break;
}
}
}
// $res_array is your sorted array now
Look at code snippet to make a multidimensional array sort in order of input
$input_format_list = [4, 1];
$data = array(
"0" => array(
"School" => array(
"id" => 1,
"name" => "ST.ANN'S HIGH SCHOOL",
)
),
"1" => array(
"School" => array(
"id" => 4,
"name" => "JYOTI VIDHYA VIHAR",
)
)
);
$result = array(); // result array
foreach($input_format_list as $key => $value){ // loop
foreach ($data as $k => $val) {
if ($data[$k]['School']['id'] === $value) {
$result[$key] = $data[$k];
}
}
}
return $result;
Take a look at array_multisort. I'm not completely sure how to use it, as I have never found a practical use for it (I prefer to use usort to clearly define my terms), but it might work for you.
<?php
$data = array(
"item1"=>"1",
"item2"=>"3",
"item3"=>"5",
"item4"=>"2",
"item5"=>"4"
);
$result=array_flip($data);
krsort($result);
$result=array_flip($result);
print_r($result);
//use rsort for the index array
$sortingArr = array("5","4","3","2","1");
print_r($sortingArr);
I'm pretty proud of my solution:
uasort($data, function($a, $b) use ($sortingArr) {
return array_search($a, $sortingArr) <=> array_search($b, $sortingArr);
});
Working example: https://3v4l.org/bbIk2
It uses uasort to maintain the key-value associations as the OP requested. (unlike #hassan's otherwise elegant solution)
It doesn't require that every element in the $data array be present in the sorting array. (like #HamZa's solution)
It's brief.
It uses the spaceship operator <=> for comparison instead of more verbose logic.
Code:
Expanding on the Answer of Andrew, if you want the undefined entries in the sorting array to appear at the end of the output array:
uasort($currentTags, function ($a, $b) use ($sortingArr) {
if (in_array($a, $sortingArr) && !in_array($b, $sortingArr)) return -1;
if (!in_array($a, $sortingArr) && in_array($b, $sortingArr)) return 1;
if (!in_array($b, $sortingArr)) return -1;
return array_search($a, $sortingArr) <=> array_search($b, $sortingArr);
});
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.