I have two array
first array:
Array (
[01-1970] => 0.00
[03-2019] => 4350.00
[05-2019] => 150.00
[06-2019] => 50.00
)
second array:
Array (
[03-2019] => 0.00
[04-2019] => 0.00
[06-2019] => 34.83
)
My expected sum result is:
Array (
[01-1970] => 0.00
[03-2019] => 4350
[04-2019] => 0.00
[05-2019] => 150.00
[06-2019] => 84.83
)
How can achieve this?
You can use array_keys to get the unique from both of the array and then loop through keys to some them
$r = [];
$keys = array_keys($a1+$a2);
foreach($keys as $v){
$r[$v] = (empty($a1[$v]) ? 0 : $a1[$v]) + (empty($a2[$v]) ? 0 : $a2[$v]);
}
Working DEMO
Your best bet is to loop the arrays individually, and sum up the values into a resulting array as you go. We can create a new array that contains the two arrays them to shorten our code a bit (see how we define [$first, $second] as the first loop).
This removes any problems with mixed lengths, and keeps all the keys and values in the array intact.
$result = [];
// Loop over our two arrays, here called $first and $second
foreach ([$first, $second] as $a) {
// Loop over the values in each array
foreach ($a as $k=>$v) {
// If the index is new to the $result array, define it to be zero (to avoid undefined index notices)
if (!isset($result[$k]))
$result[$k] = 0;
// Sum up the value!
$result[$k] += $v;
}
}
print_r($result);
Live demo at https://3v4l.org/X4ijP
You can make use of a function I made:
<?php
function array_sum_multi($arrayOne, $arrayTwo)
{
# get rid of keys
$valuesOne = array_values($arrayOne);
$valuesTwo = array_values($arrayTwo);
//create return array
$output = [];
# loop that shizzle
for ($i = 0; $i < count($valuesOne); $i++)
{
$output[$i] = $valuesOne[$i] + (!empty($valuesTwo[$i]) ? $valuesTwo[$i] : 0);
}
return $output;
}
$result = array_sum_multi([0.00, 4350.00, 150.00, 50.00], [0.00, 0.00, 34.83]);
# then for your keys:
$result = array_combine(array_keys($yourFirstArray), $result);
echo '<pre>'. print_r($result, 1) .'</pre>';
$result = $first_array; // just copy array into result
// scan second array
foreach ($second_array as $k => $v) {
// if key already exists, then add, else just set
$result[$k] = isset($result[$k]) ? ($result[$k] + $v) : $v;
}
// done
print_r($result);
An easy way to implement it would be to loop through each array, and add it to a common array with the same key.
Looping through only one array would result in a lack of a few elements if the first array is smaller than the second one or if some element from the second array are not present in the first one.
So let's just loop through both of them and add it to sum.
$sum = [];
foreach($firstArray as $key => $value){
$sum[$key] = $value + (isset($sum[$key]) ? $sum[$key] : 0.0);
}
foreach($secondArray as $key => $value){
$sum[$key] = $value + (isset($sum[$key]) ? $sum[$key] : 0.0);
}
print_r($sum);
Try this simple method thank you,
$sum = [];
foreach($firstArray as $key => $value){
if(array_key_exists($key,$secondArray)){
$newArray = [$key=>$value+$secondArray[$key]];
$sum = array_merge($sum,$newArray);
}else{
$newArray = [$key=>$value];
$sum = array_merge($sum,$newArray);
}
}
//your final required result
var_dump($sum);
Try this,
$a1 = array (
'01-1970' => 0.00,
'03-2019' => 4350.00,
'05-2019' => 150.00,
'06-2019' => 50.00
);
$a2 = array (
'03-2019' => 0.00,
'04-2019' => 0.00,
'06-2019' => 34.83
);
$sums = array();
foreach (array_keys($a1 + $a2) as $key) {
$sums[$key] = #($a1[$key] + $a2[$key]);
}
echo "<pre>";
print_r($sums);
Here is some other solution you can use.
Cheer!
$sumArray = [];
foreach($firstArray as $key => $value) {
$sumArray[$key] = $value + ($secondArray[$key] ?? 0);
}
I would like to build a multidimensional array from an array. For example I would like
$test = array (
0 => 'Tree',
1 => 'Trunk',
2 => 'Branch',
3 => 'Limb',
4 => 'Apple',
5 => 'Seed'
);
to become
$test =
array (
'Tree' => array (
'Trunk' => array (
'Branch' => array (
'Limb' => array (
'Apple' => array (
'Seed' => array ()
)
)
)
)
)
);
or more simply
$result[Tree][Trunk][Branch][Limb][Apple][Seed] = null;
I'm trying to do this with a recursive function but i'm hitting memory limit so I'm clearly doing it wrong.
<?php
$test = array (
0 => 'Tree',
1 => 'Trunk',
2 => 'Branch',
3 => 'Limb',
4 => 'Apple',
5 => 'Seed'
);
print_r($test);
print "results of function";
print_r(buildArray($test));
function buildArray (&$array, &$build = null)
{
if (count($array) > 0)
{
//create an array, pass the array to itself removing the first value
$temp = array_values($array);
unset ($temp[0]);
$build[$array[0]] = $temp;
buildArray($build,$temp);
return $build;
}
return $build;
}
Here's an approach with foreach and without recursion, which works:
function buildArray($array)
{
$new = array();
$current = &$new;
foreach($array as $key => $value)
{
$current[$value] = array();
$current = &$current[$value];
}
return $new;
}
[ Demo ]
Now your function... first, using $build[$array[0]] without defining it as an array first produces an E_NOTICE.
Second, your function is going into infinite recursion because you are not actually modifying $array ($temp isn't the same), so count($array) > 0 will be true for all of eternity.
And even if you were modifying $array, you couldn't use $array[0] anymore, because you unset that, and the indices don't just slide up. You would need array_shift for that.
After that, you pass $build and $temp to your function, which results in further because you now you assign $build to $temp, therefore creating another loop in your already-infinitely-recurring loop.
I was trying to fix all of the above in your code, but eventually realized that my code was now pretty much exactly the one from Pevara's answer, just with different variable names, so... that's that.
This function works recursively and does the trick:
function buildArray($from, $to = []) {
if (empty($from)) { return null; }
$to[array_shift($from)] = buildArray($from, $to);
return $to;
}
In your code I would expect you see an error. You are talking to $build in your first iteration as if it where an array, while you have defaulted it to null.
It seems to be easy
$res = array();
$i = count($test);
while ($i)
$res = array($test[--$i] => $res);
var_export($res);
return
array ( 'Tree' => array ( 'Trunk' => array ( 'Branch' => array ( 'Limb' => array ( 'Apple' => array ( 'Seed' => array ( ), ), ), ), ), ), )
Using a pointer, keep re-pointing it deeper. Your two output examples gave array() and null for the deepest value; this gives array() but if you want null, replace $p[$value] = array(); with $p[$value] = $test ? array() : null;
$test = array(
'Tree',
'Trunk',
'Branch',
'Limb',
'Apple',
'Seed'
);
$output = array();
$p = &$output;
while ($test) {
$value = array_shift($test);
$p[$value] = array();
$p = &$p[$value];
}
print_r($output);
I have an array with the following format:
Array
(
[0] => Array
(
[DateTime] => "2013-05-22 14:21:01"
[Price] => 102.01
)
[1] => Array
(
[DateTime] => "2013-05-23 15:55:01"
[Price] => 52.60
)
[2] => Array
(
[DateTime] => "2013-05-25 14:23:01"
[Price] => 452.25
)
... etc
)
I need to discover the lowest and highest value of Price.
min only returns they key. I've also tried max(array_map("max", $data)) but that only returns 452.25.
Will I have to use a foreach and do it manually?
Here's one way to get the min and max values:
$min = min(array_column($array, 'Price'));
$max = max(array_column($array, 'Price'));
To return the nested array for the min and max:
$prices = array_column($array, 'Price');
$min_array = $array[array_search(min($prices), $prices)];
$max_array = $array[array_search(max($prices), $prices)];
You could do each in one line since that looked like what you were trying to do:
$min_array = $array[array_search(min($prices = array_column($array, 'Price')), $prices)];
$max_array = $array[array_search(max($prices = array_column($array, 'Price')), $prices)];
PHP >= 5.5.0 needed for array_column() or use the PHP Implementation of array_column().
Using array_map() to get just the min and max:
$min = min(array_map(function($a) { return $a['Price']; }, $array));
$max = max(array_map(function($a) { return $a['Price']; }, $array));
There's probably a good array_filter() or array_reduce() as well.
I like to use the array_reduce()
$a[]=array('name'=>'kokopiko','price'=>34);
$a[]=array('name'=>'kokospiko2','price'=>234);
$a[]=array('name'=>'kokospiko3','price'=>4);
$minmax = array_reduce($a, function($result, $item) {
if (!isset($result['min'])) {
$result['min']=$item;
}
if ($result['min']['price'] > $item['price']) {
$result['min']=$item;
}
if (!isset($result['max'])) {
$result['max']=$item;
}
if ($result['max']['price'] < $item['price']) {
$result['max']=$item;
}
return $result;
});
var_dump($minmax);
shorter version
$a[]=array('name'=>'kokopiko','price'=>34);
$a[]=array('name'=>'kokospiko2','price'=>234);
$a[]=array('name'=>'kokospiko3','price'=>4);
$init=array('min'=>$a[0],'max'=>$a[0]);
$minmax = array_reduce($a, function($result, $item) {
($result['min']['price'] < $item['price'])?:$result['min']=$item;
($result['max']['price'] > $item['price'])?:$result['max']=$item;
return $result;
}, $init);
Only min/max values ( not associated array elements
$min= array_reduce($a, function($result, $item) {return min($result, $item['price']);}, $a[0]['price']);
$max= array_reduce($a, function($result, $item) {return max($result, $item['price']);}, $a[0]['price']);
I think best way (easiest way) is get all prices from your array and store in a separate arrays.
Then you extract the maximum value from the new array.
Try this:
$myarray = array ( array( "DateTime" => "2013-05-22 14:21:01", "Price" => 102.01),
array( "DateTime" => "2013-05-23 15:55:01", "Price" => 52.60),
array( "DateTime" => "2013-05-25 14:23:01", "Price" => 452.25)
);
//$key is index of $myarray and $value is one of subarrays
//declare a new array to store all prices
$all_price = array();
foreach ($myarray as $key => $value)
{
//get only "Price" from each row of array (discard "DateTime")
$all_price[] = $value["Price"];
}
//$all_price cointains now all prices and you can get min and max
$min = min($all_price);
$max = max($all_price);
echo("Min: ".$min."<br />");
echo("Max: ".$max."<br />");
Copy and paste this code into http://www.writephponline.com/
to see the result! :D
Works also on PHP lower than 5.5.0
If you have an associative array:
Array
(
[uid] => Marvelous
[status] => 1
[set_later] => Array
(
[0] => 1
[1] => 0
)
[op] => Submit
[submit] => Submit
)
And you want to access the 2nd item, how would you do it? $arr[1] doesn't seem to be working:
foreach ($form_state['values']['set_later'] as $fieldKey => $setLater) {
if (! $setLater) {
$valueForAll = $form_state['values'][$fieldKey];
$_SESSION[SET_NOW_KEY][array_search($valueForAll, $form_state['values'])] = $valueForAll; // this isn't getting the value properly
}
}
This code is supposed to produce:
$_SESSION[SET_NOW_KEY]['status'] = 1
But it just produces a blank entry.
Use array_slice
$second = array_slice($array, 1, 1, true); // array("status" => 1)
// or
list($value) = array_slice($array, 1, 1); // 1
// or
$blah = array_slice($array, 1, 1); // array(0 => 1)
$value = $blah[0];
I am a bit confused. Your code does not appear to have the correct keys for the array. However, if you wish to grab just the second element in an array, you could use:
$keys = array_keys($inArray);
$key = $keys[1];
$value = $inArray[$key];
However, after considering what it appears you're trying to do, something like this might work better:
$ii = 0;
$setLaterArr = $form_state['values']['set_later'];
foreach($form_state['values'] as $key => $value) {
if($key == 'set_later')
continue;
$setLater = $setLaterArr[$ii];
if(! $setLater) {
$_SESSION[SET_NOW_KEY][$key] = $value;
}
$ii ++;
}
Does that help? It seems you are trying to set the session value if the set_later value is not set. The above code does this. Instead of iterating through the inner array, however, it iterates through the outer array and uses an index to track where it is in the inner array. This should be reasonably performant.
You can use array_slice to get the second item:
$a= array(
'hello'=> 'world',
'how'=> 'are you',
'an'=> 'array',
);
$second= array_slice($a, 1, 1, true);
var_dump($second);
Here's a one line way to do it with array_slice and current
$value = current(array_slice($array, 1, 1)); // returns value only
If the array you provide in the first example corresponds to $form_state then
$form_state['values']['set_later'][1]
will work.
Otherwise
$i = 0;
foreach ($form_state['values']['set_later'] as $fieldKey => $setLater) {
if ($i == 1) {
$valueForAll = $form_state['values'][$fieldKey];
$_SESSION[SET_NOW_KEY][$fieldKey] = $setLater;
continue;
}
$i++;
}
Every one of the responses here are focused on getting the second element, independently on how the array is formed.
If this is your case.
Array
(
[uid] => Marvelous
[status] => 1
[set_later] => Array
(
[0] => 1
[1] => 0
)
[op] => Submit
[submit] => Submit
)
Then you can get the value of the second element via $array['status'].
Also this code
foreach ($form_state['values']['set_later'] as $fieldKey => $setLater) {
if (! $setLater) {
$valueForAll = $form_state['values'][$fieldKey];
$_SESSION[SET_NOW_KEY][array_search($valueForAll, $form_state['values'])] = $valueForAll; // this isn't getting the value properly
}
}
I don't understand what are you trying to do, care to explain?
/**
* Get nth item from an associative array
*
*
* #param $arr
* #param int $nth
*
* #return array
*/
function getNthItemFromArr($arr, $nth = 0){
$nth = intval($nth);
if(is_array($arr) && sizeof($arr) > 0 && $nth > 0){
$arr = array_slice($arr,$nth-1, 1, true);
}
return $arr;
}//end function getNthItemFromArr
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.