I have a loop that builds an array of associative arrays that looks like this:
array(
'foo' => '',
'bar' => '',
'thingys' => array()
)
on each iteration of the loop, I want to search through the array for an associate array that's 'foo' and 'bar' properties match those of the current associate array. If it exists I want to append the thingys property of the current associative array to the match. Otherwise append the entire thing.
I know how to do this with for loops, but I'm wondering if there is a simpler way to do this with an array function. I'm on php 5.3.
Example
<?php
$arr = array(
array(
'foo' => 1,
'bar' => 2,
'thing' => 'apple'
),
array(
'foo' => 1,
'bar' => 2,
'thing' => 'orange'
),
array(
'foo' => 2,
'bar' => 2,
'thing' => 'apple'
),
);
$newArr = array();
for ($i=0; $i < count($arr); $i++) {
$matchFound = false;
for ($j=0; $j < count($newArr); $j++) {
if ($arr[$i]['foo'] === $newArr[$j]['foo'] && $arr[$i]['bar'] === $newArr[$j]['bar']) {
array_push($newArr[$j]['thing'], $arr[$i]['things']);
$matchFound = true;
break;
}
}
if (!$matchFound) {
array_push($newArr,
array(
'foo' => $arr[$i]['foo'],
'bar' => $arr[$i]['bar'],
'things' => array($arr[$i]['thing'])
)
);
}
}
/*Output
$newArr = array(
array(
'foo' => 1,
'bar' => 2,
'things' => array('orange', 'apple')
),
array(
'foo' => 2,
'bar' => 2,
'things' => array('apple')
),
)
*/
?>
I don't know if it is possible through a built-in function, but I think no. Something can be implemented through array_map, but anyway you have to perform a double loop.
I propose you a one-loop solution using a temporary array ($keys) as index of already created $newArr items, based on foo and bar; elements of original array are processed through a foreach loop, and if a $keys element with first key as foo value and second key as bar value exists, then the current thing value is added to the returned key index of $newArr, otherwise a new $newArray element is created.
$newArr = $keys = array();
foreach( $arr as $row )
{
if( isset( $keys[$row['foo']][$row['bar']] ) )
{ $newArr[$keys[$row['foo']][$row['bar']]]['thing'][] = $row['thing']; }
else
{
$keys[$row['foo']][$row['bar']] = array_push( $newArr, $row )-1;
$newArr[$keys[$row['foo']][$row['bar']]]['thing'] = array( $row['thing'] );
}
}
unset( $keys );
3v4l.org demo
Edit: array_map variant
This is the same solution above, using array_map instead of foreach loop. Note that also your original code can be converted in this way.
$newArr = $keys = array();
function filterArr( $row )
{
global $newArr, $keys;
if( isset( $keys[$row['foo']][$row['bar']] ) )
{ $newArr[$keys[$row['foo']][$row['bar']]]['thing'][] = $row['thing']; }
else
{
$keys[$row['foo']][$row['bar']] = array_push( $newArr, $row )-1;
$newArr[$keys[$row['foo']][$row['bar']]]['thing'] = array( $row['thing'] );
}
}
array_map( 'filterArr', $arr );
3v4l.org demo
Might be a newbie question but I've been trying to figure this problem and it's doing my head in.
I have the following array :
[0] => Array
(
[provisionalBookingRoomID] => 1
[totalSpecificRoomCount] => 2
)
[1] => Array
(
[provisionalBookingRoomID] => 2
[totalSpecificRoomCount] => 5
)
I need a php function that searches through the array for the value of 'provisionalBookingRoomID' and returns the value of 'totalSpecificRoomCount'
basically something like the following
getProvisionalTotalRoomsCount($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;
I need to assign in an associative array a number as key name, but if I do:
// Places (generated by mysql)
$places = array (
0 => '1234',
1 => '2345'
);
// Week stats (generated by mysql)
$week = array (
1234 =>
array (
0 =>
array (
'iid' => '1234',
'mid' => 'xxxxxxxx',
'name' => 'Name1',
),
1 =>
array (
'iid' => '1234',
'mid' => 'xxxxxxxx',
'name' => 'Name3',
)
),
2345 =>
array (
0 =>
array (
'iid' => '2345',
'mid' => 'xxxxxxxx',
'name' => 'Name2',
),
2 =>
array (
'iid' => '2345',
'mid' => 'xxxxxxxx',
'name' => 'Name4',
)
)
);
foreach($places as &$place) {
echo $place;
$i = 0;
foreach($week[$i] as &$value) {
echo $value["name"];
$i++;
}
}
it doesn't work:
http://codepad.viper-7.com/Y1g37t
because seems I should call it with:
echo $arr[<specific index>];
Instead I need to set "1234" and "2345" as strings, like this array:
$arr = Array("foo" => "bar");
So I can call it with
$arr[0] // bar
How can I do?
Solution
Thanks to #kirilloid
i use this code:
$vararr = array_keys($week);
$key = $vararr[$i];
To get the key
It because it's an map and map associates values to keys so you have to do this :
<?php
$myNumber = 1234;
$myValue = "foo";
$arr = Array( $myNumber => $myValue );
echo $arr[1234];
?>
And don't forget to replace the ":" at your first line !
To iterate on a "map" you can use the foreach function :
foreach($arr as $key=>$value) {
echo $key;
echo $value;
}
This should display your key and the value associated :
1234
foo
Here is the difference with a simple array:
$array = array("foo", "bar", "hallo", "world");
echo $array[0];
You may either use array_keys:
echo $arr[array_keys($arr)[0]];
or reset and current:
reset($arr);
echo current($arr);
There is no problem here - this is how it is supposed to work.
If you create an array like this:
$myNumber = 1234;
$myValue = "foo";
$arr = Array( $myNumber => $myValue );
then the index of the element is 1234, not 0.
You can retrieve it with echo $arr[1234]
If you need to loop over the array you can do so with
foreach($arr as $key=>$value) {
// do something with $value
}
There is no problem. As the value of $myNumber is 1234, you should access the array element like this:
echo $arr[1234];
If you need to access them in a foor loop you can get the keys as an array:
$keys = array_keys($arr);
$keys_count = count($keys);
for ($i=0; i<$keys_count; $i++) {
echo $arr[$keys[$i]];
}
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.