Related
How to check two arrays and search for matching keys and merge the values of the 1st array with the matching keys of the second array.Please help me as I'm new to this.
example :
1st array = {id => 11,name => 'name',age => 18 }
2nd array = {id,name,age,school}
I want to get the result by adding the matching values to the 2nd array
2nd array = {id => 11,name => 'name',age => 18,school => }
try this
$a = ['id' => 11,'name' => 'name','age' => 18];
$b = array_flip(['id','name','age','school']);
foreach($b as $key => &$value){
$value = '';
}
$result = array_merge($b, $a);
One of the simple way is looping
$first= array('id' => 11,'name' => 'name','age' => 18 );
$second = array('id','name','age','school');
foreach ($second as $value) {
if(isset($first[$value])){
$final[$value] = $first[$value];
}
};
print_r($final);
Second Array flip and array merge
$first = ['id' => 11,'name' => 'name','age' => 18];
$second= array_flip(['id','name','age','school']);
foreach($second as $key => s$value){
$value = '';
}
$result = array_merge($second, $first);
print_r($result);
Use array_merge
<?php
$array1 = array('id' => '11', 'name' => 'name', 'age' => 18);
$array2 = array('id','name','age','school');
$array3 = array_merge(array_fill_keys($array2, null), $array1);
print_r($array3);
?>
I have an array like below
$old = array(
'a' => 'blah',
'b' => 'key',
'c' => 'amazing',
'd' => array(
0 => 'want to replace',
1 => 'yes I want to'
)
);
I have another array having keys to replace with key information.
$keyReplaceInfoz = array('a' => 'newA', 'b' => 'newB', 'c' => 'newC', 'd' => 'newD');
I need to replace all keys of array $old with respective values in array $keyReplaceInfo.
Output should be like this
$old = array(
'newA' => 'blah',
'newB' => 'key',
'newC' => 'amazing',
'newD' => array(
0 => 'want to replace',
1 => 'yes I want to'
)
);
I had to do it manually as below. I am expecting better option. can anyone suggest better way to accomplish this?
$new = array();
foreach ($old as $key => $value)
{
$new[$keyReplaceInfoz[$key]] = $value;
}
I know this can be more simpler.
array_combine(array_merge($old, $keyReplaceInfoz), $old)
I think this looks easier than what you posed.
array_combine(
['newKey1', 'newKey2', 'newKey3'],
array_values(['oldKey1' => 1, 'oldKey2' => 2, 'oldKey3' => 3])
);
This should do the trick as long as you have the same number of values and the same order.
IMO using array_combine, array_merge, even array_intersect_key is overkill.
The original code is good enough, and very fast.
Adapting #shawn-k solution, here is more cleaner code using array_walk, it will only replace desired keys, of course you can modify as per your convenience
array_walk($old, function($value,$key)use ($keyReplaceInfoz,&$old){
$newkey = array_key_exists($key,$keyReplaceInfoz)?$keyReplaceInfoz[$key]:false;
if($newkey!==false){$old[$newkey] = $value;unset($old[$key]);
}
});
print_r($old);
I just solved this same problem in my own application, but for my application $keyReplaceInfoz acts like the whitelist- if a key is not found, that whole element is removed from the resulting array, while the matching whitelisted keys get translated to the new values.
I suppose you could apply this same algorithm maybe with less total code by clever usage of array_map (http://php.net/manual/en/function.array-map.php), which perhaps another generous reader will do.
function filterOldToAllowedNew($key_to_test){
return isset($keyReplaceInfoz[$key_to_test])?$keyReplaceInfoz[$key_to_test]:false;
}
$newArray = array();
foreach($old as $key => $value){
$newkey = filterOldToAllowedNew($key);
if($newkey){
$newArray[$newkey] = $value;
}
}
print_r($newArray);
This question is old but since it comes up first on Google I thought I'd add solution.
// Subject
$old = array('foo' => 1, 'baz' => 2, 'bar' => 3));
// Translations
$tr = array('foo'=>'FOO', 'bar'=>'BAR');
// Get result
$new = array_combine(preg_replace(array_map(function($s){return "/^$s$/";},
array_keys($tr)),$tr, array_keys($old)), $old);
// Output
print_r($new);
Result:
Array
(
[FOO] => 1
[baz] => 2
[BAR] => 3
)
This the solution i have implemented for the same subject:
/**
* Replace keys of given array by values of $keys
* $keys format is [$oldKey=>$newKey]
*
* With $filter==true, will remove elements with key not in $keys
*
* #param array $array
* #param array $keys
* #param boolean $filter
*
* #return $array
*/
function array_replace_keys(array $array,array $keys,$filter=false)
{
$newArray=[];
foreach($array as $key=>$value)
{
if(isset($keys[$key]))
{
$newArray[$keys[$key]]=$value;
}
elseif(!$filter)
{
$newArray[$key]=$value;
}
}
return $newArray;
}
This works irrespective of array order & array count. Output order & value will be based on replaceKey.
$replaceKey = array('a' => 'newA', 'b' => 'newB', 'c' => 'newC', 'd' => 'newD', 'e' => 'newE','f'=>'newF');
$array = array(
'a' => 'blah',
'd' => array(
0 => 'want to replace',
1 => 'yes I want to'
),
'noKey'=>'RESIDUAL',
'c' => 'amazing',
'b' => 'key',
);
$filterKey = array_intersect_key($replaceKey,$array);
$filterarray = array_intersect_key(array_merge($filterKey,$array),$filterKey);
$replaced = array_combine($filterKey,$filterarray);
//output
var_export($replaced);
//array ( 'newA' => 'blah', 'newB' => 'key', 'newC' => 'amazing', 'newD' => array ( 0 => 'want to replace', 1 => 'yes I want to' ) )
If you're looking for a recursive solution to use on a multidimensional array, have a look at the below method. It will replace all keys requested, and leave all other keys alone.
/**
* Given an array and a set of `old => new` keys,
* will recursively replace all array keys that
* are old with their corresponding new value.
*
* #param mixed $array
* #param array $old_to_new_keys
*
* #return array
*/
function array_replace_keys($array, array $old_to_new_keys)
{
if(!is_array($array)){
return $array;
}
$temp_array = [];
$ak = array_keys($old_to_new_keys);
$av = array_values($old_to_new_keys);
foreach($array as $key => $value){
if(array_search($key, $ak, true) !== false){
$key = $av[array_search($key, $ak)];
}
if(is_array($value)){
$value = array_replace_keys($value, $old_to_new_keys);
}
$temp_array[$key] = $value;
}
return $temp_array;
}
Using OP's example array:
$old = array(
'a' => 'blah',
'b' => 'key',
'c' => 'amazing',
'd' => array(
0 => 'want to replace',
1 => 'yes I want to'
)
);
$replace = ["a" => "AA", 1 => 11];
var_export(array_replace_keys($old, $replace));
Gives the following output:
array (
'AA' => 'blah',
'b' => 'key',
'c' => 'amazing',
'd' =>
array (
0 => 'want to replace',
11 => 'yes I want to',
),
)
DEMO
Inspired by the following snippet.
This uses #Summoner's example but keeps #Leigh's hint in mind:
$start = microtime();
$array = [ "a" => 1, "b" => 2, "c" => 3 ];
function array_replace_key($array, $oldKey, $newKey) {
$keys = array_keys($array);
$idx = array_search($oldKey, $keys);
array_splice($keys, $idx, 1, $newKey);
return array_combine($keys, array_values($array));
}
print_r(array_replace_key($array, "b", "z"));
<?php
$new = array();
foreach ($old as $key => $value)
{
$new[$keyReplaceInfoz][$key] = $value;
}
?>
This question already has answers here:
Merge two indexed arrays of indexed arrays based on first column value
(2 answers)
Closed 5 months ago.
I need to compare two 2D arrays in PHP. The arrays look like this:
Array one
ID Name
11 Aa
11 Ab
12 Bb
13 Cc
14 Dd
15 Ee
Array two
ID Content
11 Cat
13 Dog
14 Donkey
Now I'd need to combine these two into an array like this:
ID Name Conent
11 Aa Cat
11 Ab Cat
12 Bb
13 Cc Dog
14 Dd Donkey
15 Ee
How can I accomplish this? I have had no luck with array_merge() or $array3 = $array1 + $array2;
A quick way would be to iterate over the first array and append the value from the second:
$array1 = array('11' => 'Aa', '12' => 'Bb', '13' => 'Cc', '14' => 'Dd', '15' => 'Ee');
$array2 = array('11' => 'Cat', '13' => 'Dog', '14' => 'Donkey');
$combined = array();
foreach ($array1 as $key => $val) {
$combined[$key] = $val . (isset($array2[$key]) ? ' '.$array2[$key] : '');
}
This will loop through every key/value in $array1 and add it to the $combined array. If a value in $array2 exists with the same index, it will append it to that value from $array1, separated with a space.
UPDATE: I misread the format of the arrays (again). I assumed ID was the actual index in the array, but as the example array output has both Name and Content, I'm assuming ID is an actual index string value and not the index in the array itself. To stick with the loop scenario, you can iterate through the first array and have a nested loop iterate through the second:
$array1 = array(
array('ID' => '11', 'Name' => 'Aa'),
array('ID' => '12', 'Name' => 'Bb'),
array('ID' => '13', 'Name' => 'Cc'),
array('ID' => '14', 'Name' => 'Dd'),
array('ID' => '15', 'Name' => 'Ee'),
);
$array2 = array(
array('ID' => '11', 'Content' => 'Cat'),
array('ID' => '13', 'Content' => 'Dog'),
array('ID' => '14', 'Content' => 'Donkey')
);
$combined = array();
foreach ($array1 as $arr) {
$comb = array('ID' => $arr['ID'], 'Name' => $arr['Name'], 'Content' => '');
foreach ($array2 as $arr2) {
if ($arr2['ID'] == $arr['ID']) {
$comb['Content'] = $arr2['Content'];
break;
}
}
$combined[] = $comb;
}
This will add every value in $array1 to the combined array and if, and only if, a value in $array2 contains the same ID field will it add it's Content field to the array too. This can be extended to handle any number of fields as well, either by name, or by changing the inner-if block to have $comb += $arr2; instead (which should merge all non-existing indexes).
You will have to make your own function:
function putThemTogether($array1, $array2) {
$output = array();
foreach($array1 as $key => $value) {
if (!isset($output[$key]))
$output[$key] = array();
$output[$key][] = $value;
}
foreach($array2 as $key => $value) {
if (!isset($output[$key]))
$output[$key] = array();
$output[$key][] = $value;
}
return $output;
}
To make this better you could make it take an arbitrary number of arguments.
$result = array_map (
function ($item) { return is_array($item) ? implode(' ', $item) : $item; },
array_merge_recursive($array1, $array2);
);
Note, that both arrays require string keys
Another solution for this is to use array_search and array_column (since PHP 5.5.0).
foreach ($array1 as $key => $val) {
$found_key = array_search($val['ID'], array_column($array2, 'ID'));
if ($found_key !== false) { $array1[$key]['Content'] = $array2[$found_key]['Content']; }
}
Try this I hope It'll work
function merge_two_arrays($array1,$array2) {
$data = array();
$arrayAB = array_merge($array1,$array2);
foreach ($arrayAB as $value) {
// This assumes there is a field called "id"
$id = $value['id'];
if (!isset($data[$id])) {
$data[$id] = array();
}
$data[$id] = array_merge($data[$id],$value);
}
return $data;
}
$master_array = merge_two_arrays($array1,$array2);
How can I add all the columnar values by associative key? Note that key sets are dynamic.
Input array:
Array
(
[0] => Array
(
[gozhi] => 2
[uzorong] => 1
[ngangla] => 4
[langthel] => 5
)
[1] => Array
(
[gozhi] => 5
[uzorong] => 0
[ngangla] => 3
[langthel] => 2
)
[2] => Array
(
[gozhi] => 3
[uzorong] => 0
[ngangla] => 1
[langthel] => 3
)
)
Desired result:
Array
(
[gozhi] => 10
[uzorong] => 1
[ngangla] => 8
[langthel] => 10
)
You can use array_walk_recursive() to get a general-case solution for your problem (the one when each inner array can possibly have unique keys).
$final = array();
array_walk_recursive($input, function($item, $key) use (&$final){
$final[$key] = isset($final[$key]) ? $item + $final[$key] : $item;
});
Example with array_walk_recursive() for the general case
Also, since PHP 5.5 you can use the array_column() function to achieve the result you want for the exact key, [gozhi], for example :
array_sum(array_column($input, 'gozhi'));
Example with array_column() for the specified key
If you want to get the total sum of all inner arrays with the same keys (the desired result that you've posted), you can do something like this (bearing in mind that the first inner array must have the same structure as the others) :
$final = array_shift($input);
foreach ($final as $key => &$value){
$value += array_sum(array_column($input, $key));
}
unset($value);
Example with array_column() in case all inner arrays have the same keys
If you want a general-case solution using array_column() then at first you may consider to get all unique keys , and then get the sum for each key :
$final = array();
foreach($input as $value)
$final = array_merge($final, $value);
foreach($final as $key => &$value)
$value = array_sum(array_column($input, $key));
unset($value);
Example with array_column() for the general case
$sumArray = array();
foreach ($myArray as $k=>$subArray) {
foreach ($subArray as $id=>$value) {
isset($sumArray[$id]) || $sumArray[$id] = 0;
$sumArray[$id]+=$value;
}
}
print_r($sumArray);
Use this snippet:
$key = 'gozhi';
$sum = array_sum(array_column($array,$key));
Here is a solution similar to the two others:
$acc = array_shift($arr);
foreach ($arr as $val) {
foreach ($val as $key => $val) {
$acc[$key] += $val;
}
}
But this doesn’t need to check if the array keys already exist and doesn’t throw notices neither.
It can also be done using array_map :
$rArray = array(
0 => array(
'gozhi' => 2,
'uzorong' => 1,
'ngangla' => 4,
'langthel' => 5
),
1 => array(
'gozhi' => 5,
'uzorong' => 0,
'ngangla' => 3,
'langthel' => 2
),
2 => array(
'gozhi' => 3,
'uzorong' => 0,
'ngangla' => 1,
'langthel' => 3
),
);
$sumResult = call_user_func_array('array_map', array_merge(['sum'], $rArray));
function sum()
{
return array_sum(func_get_args());
}
$newarr=array();
foreach($arrs as $value)
{
foreach($value as $key=>$secondValue)
{
if(!isset($newarr[$key]))
{
$newarr[$key]=0;
}
$newarr[$key]+=$secondValue;
}
}
Another version, with some benefits below.
$sum = ArrayHelper::copyKeys($arr[0]);
foreach ($arr as $item) {
ArrayHelper::addArrays($sum, $item);
}
class ArrayHelper {
public function addArrays(Array &$to, Array $from) {
foreach ($from as $key=>$value) {
$to[$key] += $value;
}
}
public function copyKeys(Array $from, $init=0) {
return array_fill_keys(array_keys($from), $init);
}
}
I wanted to combine the best of Gumbo's, Graviton's, and Chris J's answer with the following goals so I could use this in my app:
a) Initialize the 'sum' array keys outside of the loop (Gumbo). Should help with performance on very large arrays (not tested yet!). Eliminates notices.
b) Main logic is easy to understand without hitting the manuals. (Graviton, Chris J).
c) Solve the more general problem of adding the values of any two arrays with the same keys and make it less dependent on the sub-array structure.
Unlike Gumbo's solution, you could reuse this in cases where the values are not in sub arrays. Imagine in the example below that $arr1 and $arr2 are not hard-coded, but are being returned as the result of calling a function inside a loop.
$arr1 = array(
'gozhi' => 2,
'uzorong' => 1,
'ngangla' => 4,
'langthel' => 5
);
$arr2 = array(
'gozhi' => 5,
'uzorong' => 0,
'ngangla' => 3,
'langthel' => 2
);
$sum = ArrayHelper::copyKeys($arr1);
ArrayHelper::addArrays($sum, $arr1);
ArrayHelper::addArrays($sum, $arr2);
It can also be done using array_walk:
function array_sum_values(array $input, $key) {
$sum = 0;
array_walk($input, function($item, $index, $params) {
if (!empty($item[$params[1]]))
$params[0] += $item[$params[1]];
}, array(&$sum, $key)
);
return $sum;
}
var_dump(array_sum_values($arr, 'gozhi'));
Not so readable like previous solutions but it works :)
Go through each item of the array and sum values to previous values if they exist, if not just assign the value.
<?php
$array =
[
[
'a'=>1,
'b'=>1,
'c'=>1,
],
[
'a'=>2,
'b'=>2,
],
[
'a'=>3,
'd'=>3,
]
];
$result = array_reduce($array, function($carry, $item) {
foreach($item as $k => $v)
$carry[$k] = $v + ($carry[$k] ?? 0);
return $carry;
}, []);
print_r($result);
Output:
Array
(
[a] => 6
[b] => 3
[c] => 1
[d] => 3
)
Or just loop through each sub array, and group the values for each column. Eventually summing them:
foreach($array as $subarray)
foreach($subarray as $key => $value)
$grouped[$key][] = $value;
$sums = array_map('array_sum', $grouped);
Here's a version where the array keys may not be the same for both arrays, but you want them all to be there in the final array.
function array_add_by_key( $array1, $array2 ) {
foreach ( $array2 as $k => $a ) {
if ( array_key_exists( $k, $array1 ) ) {
$array1[$k] += $a;
} else {
$array1[$k] = $a;
}
}
return $array1;
}
We need to check first if array key does exist.
CODE:
$sum = array();
foreach ($array as $key => $sub_array) {
foreach ($sub_array as $sub_key => $value) {
//If array key doesn't exists then create and initize first before we add a value.
//Without this we will have an Undefined index error.
if( ! array_key_exists($sub_key, $sum)) $sum[$sub_key] = 0;
//Add Value
$sum[$sub_key]+=$value;
}
}
print_r($sum);
OUTPUT With Array Key Validation:
Array
(
[gozhi] => 10
[uzorong] => 1
[ngangla] => 8
[langthel] => 10
)
OUTPUT Without Array Key Validation:
Notice: Undefined index: gozhi in F:\web\index.php on line 37
Notice: Undefined index: uzorong in F:\web\index.php on line 37
Notice: Undefined index: ngangla in F:\web\index.php on line 37
Notice: Undefined index: langthel in F:\web\index.php on line 37
Array
(
[gozhi] => 10
[uzorong] => 1
[ngangla] => 8
[langthel] => 10
)
This is a bad practice although it prints the output. Always check first if key does exist.
Simple example with array_reduce()
$numbers = [10,20,30];
$total = 0;
foreach ($numbers as $number) {
$total += $number;
}
echo $total; // 60
=>
$numbers = [10,20,30];
$total = array_reduce($numbers, function ($previous, $current) {
return $previous + $current;
});
echo $total; // 60
With assoc array:
$carts = [
['item' => 'A', 'qty' => 2, 'price' => 10],
['item' => 'B', 'qty' => 3, 'price' => 20],
['item' => 'C', 'qty' => 5, 'price' => 30]
];
$total = array_reduce(
$carts,
function ($prev, $item) {
return $prev + $item['qty'] * $item['price'];
}
);
echo $total; // 155
More info => https://www.phptutorial.net/php-tutorial/php-array_reduce/
For those who landed here and are searching for a solution that merges N arrays AND also sums the values of identical keys found in the N arrays, I've written this function that works recursively as well. (See: https://gist.github.com/Nickology/f700e319cbafab5eaedc)
Example:
$a = array( "A" => "bob", "sum" => 10, "C" => array("x","y","z" => 50) );
$b = array( "A" => "max", "sum" => 12, "C" => array("x","y","z" => 45) );
$c = array( "A" => "tom", "sum" => 8, "C" => array("x","y","z" => 50, "w" => 1) );
print_r(array_merge_recursive_numeric($a,$b,$c));
Will result in:
Array
(
[A] => tom
[sum] => 30
[C] => Array
(
[0] => x
[1] => y
[z] => 145
[w] => 1
)
)
Here's the code:
<?php
/**
* array_merge_recursive_numeric function. Merges N arrays into one array AND sums the values of identical keys.
* WARNING: If keys have values of different types, the latter values replace the previous ones.
*
* Source: https://gist.github.com/Nickology/f700e319cbafab5eaedc
* #params N arrays (all parameters must be arrays)
* #author Nick Jouannem <nick#nickology.com>
* #access public
* #return void
*/
function array_merge_recursive_numeric() {
// Gather all arrays
$arrays = func_get_args();
// If there's only one array, it's already merged
if (count($arrays)==1) {
return $arrays[0];
}
// Remove any items in $arrays that are NOT arrays
foreach($arrays as $key => $array) {
if (!is_array($array)) {
unset($arrays[$key]);
}
}
// We start by setting the first array as our final array.
// We will merge all other arrays with this one.
$final = array_shift($arrays);
foreach($arrays as $b) {
foreach($final as $key => $value) {
// If $key does not exist in $b, then it is unique and can be safely merged
if (!isset($b[$key])) {
$final[$key] = $value;
} else {
// If $key is present in $b, then we need to merge and sum numeric values in both
if ( is_numeric($value) && is_numeric($b[$key]) ) {
// If both values for these keys are numeric, we sum them
$final[$key] = $value + $b[$key];
} else if (is_array($value) && is_array($b[$key])) {
// If both values are arrays, we recursively call ourself
$final[$key] = array_merge_recursive_numeric($value, $b[$key]);
} else {
// If both keys exist but differ in type, then we cannot merge them.
// In this scenario, we will $b's value for $key is used
$final[$key] = $b[$key];
}
}
}
// Finally, we need to merge any keys that exist only in $b
foreach($b as $key => $value) {
if (!isset($final[$key])) {
$final[$key] = $value;
}
}
}
return $final;
}
?>
Here you have how I usually do this kind of operations.
// We declare an empty array in wich we will store the results
$sumArray = array();
// We loop through all the key-value pairs in $myArray
foreach ($myArray as $k=>$subArray) {
// Each value is an array, we loop through it
foreach ($subArray as $id=>$value) {
// If $sumArray has not $id as key we initialize it to zero
if(!isset($sumArray[$id])){
$sumArray[$id] = 0;
}
// If the array already has a key named $id, we increment its value
$sumArray[$id]+=$value;
}
}
print_r($sumArray);
You can try this:
$c = array_map(function () {
return array_sum(func_get_args());
},$a, $b);
and finally:
print_r($c);
this works great on my laravel project
print_r($Array); // your original array
$_SUM = [];
// count($Array[0]) => if the number of keys are equall in all arrays then do a count of index 0 etc.
for ($i=0; $i < count($Array[0]); $i++) {
$_SUM[] = $Array[0][$i] + $Array[1][$i]; // do a for loop on the count
}
print_r($_SUM); // get a sumed up array
$sumArray = array();
foreach ($myArray as $k => $subArray) {
foreach ($subArray as $id => $value) {
if (!isset($sumArray[$id])) {
$sumArray[$id] = 0;
}
$sumArray[$id]+=$value;
}
}
$sumArray = array();
foreach ($myArray as $k=>$subArray) {
foreach ($subArray as $id=>$value) {
if(!isset($sumArray[$id])){
$sumArray[$id] =$value;
}else {
$sumArray[$id]+=$value;
}
}
}
print_r($sumArray);
`
For example, you can pluck all fields from a result like this below.
I am picking out the 'balance' from an array and save to a variable
$kii = $user->pluck('balance');
then on the next line u can sum like this:
$sum = $kii->sum();
Hope it helps.
Code here:
$temp_arr = [];
foreach ($a as $k => $v) {
if(!is_null($v)) {
$sum = isset($temp_arr[$v[0]]) ? ((int)$v[5] + $sum) : (int)$v[5];
$temp_arr[$v[0]] = $sum;
}
}
return $temp_arr;
Result:
{SEQ_OK: 1328,SEQ_ERROR: 561}
How would you flip 90 degrees (transpose) a multidimensional array in PHP? For example:
// Start with this array
$foo = array(
'a' => array(
1 => 'a1',
2 => 'a2',
3 => 'a3'
),
'b' => array(
1 => 'b1',
2 => 'b2',
3 => 'b3'
),
'c' => array(
1 => 'c1',
2 => 'c2',
3 => 'c3'
)
);
$bar = flipDiagonally($foo); // Mystery function
var_dump($bar[2]);
// Desired output:
array(3) {
["a"]=>
string(2) "a2"
["b"]=>
string(2) "b2"
["c"]=>
string(2) "c2"
}
How would you implement flipDiagonally()?
Edit: this is not homework. I just want to see if any SOers have a more creative solution than the most obvious route. But since a few people have complained about this problem being too easy, what about a more general solution that works with an nth dimension array?
i.e. How would you write a function so that:
$foo[j][k][...][x][y][z] = $bar[z][k][...][x][y][j]
?(ps. I don't think 12 nested for loops is the best solution in this case.)
function transpose($array) {
array_unshift($array, null);
return call_user_func_array('array_map', $array);
}
Or if you're using PHP 5.6 or later:
function transpose($array) {
return array_map(null, ...$array);
}
With 2 loops.
function flipDiagonally($arr) {
$out = array();
foreach ($arr as $key => $subarr) {
foreach ($subarr as $subkey => $subvalue) {
$out[$subkey][$key] = $subvalue;
}
}
return $out;
}
I think you're referring to the array transpose (columns become rows, rows become columns).
Here is a function that does it for you (source):
function array_transpose($array, $selectKey = false) {
if (!is_array($array)) return false;
$return = array();
foreach($array as $key => $value) {
if (!is_array($value)) return $array;
if ($selectKey) {
if (isset($value[$selectKey])) $return[] = $value[$selectKey];
} else {
foreach ($value as $key2 => $value2) {
$return[$key2][$key] = $value2;
}
}
}
return $return;
}
Transposing an N-dimensional array:
function transpose($array, &$out, $indices = array())
{
if (is_array($array))
{
foreach ($array as $key => $val)
{
//push onto the stack of indices
$temp = $indices;
$temp[] = $key;
transpose($val, $out, $temp);
}
}
else
{
//go through the stack in reverse - make the new array
$ref = &$out;
foreach (array_reverse($indices) as $idx)
$ref = &$ref[$idx];
$ref = $array;
}
}
$foo[1][2][3][3][3] = 'a';
$foo[4][5][6][5][5] = 'b';
$out = array();
transpose($foo, $out);
echo $out[3][3][3][2][1] . ' ' . $out[5][5][6][5][4];
Really hackish, and probably not the best solution, but hey it works.
Basically it traverses the array recursively, accumulating the current indicies in an array.
Once it gets to the referenced value, it takes the "stack" of indices and reverses it, putting it into the $out array. (Is there a way of avoiding use of the $temp array?)
Codler's answer fails for a single-row matrix (e.g. [[1,2]]) and also for the empty matrix ([]), which must be special-cased:
function transpose(array $matrix): array {
if (!$matrix) return [];
return array_map(count($matrix) == 1 ? fn ($x) => [$x] : null, ...$matrix);
}
(note: PHP 7.4+ syntax, easy enough to adapt for older versions)
I got confronted with the same problem. Here is what i came up with:
function array_transpose(array $arr)
{
$keys = array_keys($arr);
$sum = array_values(array_map('count', $arr));
$transposed = array();
for ($i = 0; $i < max($sum); $i ++)
{
$item = array();
foreach ($keys as $key)
{
$item[$key] = array_key_exists($i, $arr[$key]) ? $arr[$key][$i] : NULL;
}
$transposed[] = $item;
}
return $transposed;
}
I needed a transpose function with support for associative array:
$matrix = [
['one' => 1, 'two' => 2],
['one' => 11, 'two' => 22],
['one' => 111, 'two' => 222],
];
$result = \array_transpose($matrix);
$trans = [
'one' => [1, 11, 111],
'two' => [2, 22, 222],
];
And the way back:
$matrix = [
'one' => [1, 11, 111],
'two' => [2, 22, 222],
];
$result = \array_transpose($matrix);
$trans = [
['one' => 1, 'two' => 2],
['one' => 11, 'two' => 22],
['one' => 111, 'two' => 222],
];
The array_unshift trick did not work NOR the array_map...
So I've coded a array_map_join_array function to deal with record keys association:
/**
* Similar to array_map() but tries to join values on intern keys.
* #param callable $callback takes 2 args, the intern key and the list of associated values keyed by array (extern) keys.
* #param array $arrays the list of arrays to map keyed by extern keys NB like call_user_func_array()
* #return array
*/
function array_map_join_array(callable $callback, array $arrays)
{
$keys = [];
// try to list all intern keys
array_walk($arrays, function ($array) use (&$keys) {
$keys = array_merge($keys, array_keys($array));
});
$keys = array_unique($keys);
$res = [];
// for each intern key
foreach ($keys as $key) {
$items = [];
// walk through each array
array_walk($arrays, function ($array, $arrKey) use ($key, &$items) {
if (isset($array[$key])) {
// stack/transpose existing value for intern key with the array (extern) key
$items[$arrKey] = $array[$key];
} else {
// or stack a null value with the array (extern) key
$items[$arrKey] = null;
}
});
// call the callback with intern key and all the associated values keyed with array (extern) keys
$res[$key] = call_user_func($callback, $key, $items);
}
return $res;
}
and array_transpose became obvious:
function array_transpose(array $matrix)
{
return \array_map_join_array(function ($key, $items) {
return $items;
}, $matrix);
}
We can do this by using Two foreach. Traveling one array and another array to create new arrayLike This:
$foo = array(
'a' => array(
1 => 'a1',
2 => 'a2',
3 => 'a3'
),
'b' => array(
1 => 'b1',
2 => 'b2',
3 => 'b3'
),
'c' => array(
1 => 'c1',
2 => 'c2',
3 => 'c3'
)
);
$newFoo = [];
foreach($foo as $a => $k){
foreach($k as $i => $j){
$newFoo[$i][]= $j;
}
}
Check The Output
echo "<pre>";
print_r($newFoo);
echo "</pre>";
Before I start, I'd like to say thanks again to #quazardus for posting his generalised solution for tranposing any two dimenional associative (or non-associative) array!
As I am in the habit of writing my code as tersely as possible I went on to "minimizing" his code a little further. This will very likely not be to everybody's taste. But just in case anyone should be interested, here is my take on his solution:
function arrayMap($cb, array $arrays) // $cb: optional callback function
{ $keys = [];
array_walk($arrays, function ($array) use (&$keys)
{ $keys = array_merge($keys, array_keys($array)); });
$keys = array_unique($keys); $res = [];
foreach ($keys as $key) {
$items = array_map(function ($arr) use ($key)
{return isset($arr[$key]) ? $arr[$key] : null; },$arrays);
$res[$key] = call_user_func(
is_callable($cb) ? $cb
: function($k, $itms){return $itms;},
$key, $items);
}
return $res;
}
Now, analogous to the PHP standard function array_map(), when you call
arrayMap(null,$b);
you will get the desired transposed matrix.
This is another way to do the exact same thing which #codler s answer does. I had to dump some arrays in csv so I used the following function:
function transposeCsvData($data)
{
$ct=0;
foreach($data as $key => $val)
{
//echo count($val);
if($ct< count($val))
$ct=count($val);
}
//echo $ct;
$blank=array_fill(0,$ct,array_fill(0,count($data),null));
//print_r($blank);
$retData = array();
foreach ($data as $row => $columns)
{
foreach ($columns as $row2 => $column2)
{
$retData[$row2][$row] = $column2;
}
}
$final=array();
foreach($retData as $k=>$aval)
{
$final[]=array_replace($blank[$k], $aval);
}
return $final;
}
Test and output reference: https://tutes.in/how-to-transpose-an-array-in-php-with-irregular-subarray-size/
Here is array_walk way to achieve this,
function flipDiagonally($foo){
$temp = [];
array_walk($foo, function($item,$key) use(&$temp){
foreach($item as $k => $v){
$temp[$k][$key] = $v;
}
});
return $temp;
}
$bar = flipDiagonally($foo); // Mystery function
Demo.
Here's a variation of Codler/Andreas's solution that works with associative arrays. Somewhat longer but loop-less purely functional:
<?php
function transpose($array) {
$keys = array_keys($array);
return array_map(function($array) use ($keys) {
return array_combine($keys, $array);
}, array_map(null, ...array_values($array)));
}
Example:
<?php
$foo = array(
"fooA" => [ "a1", "a2", "a3"],
"fooB" => [ "b1", "b2", "b3"],
"fooC" => [ "c1", "c2", "c3"]
);
print_r( transpose( $foo ));
// Output like this:
Array (
[0] => Array (
[fooA] => a1
[fooB] => b1
[fooC] => c1
)
[1] => Array (
[fooA] => a2
[fooB] => b2
[fooC] => c2
)
[2] => Array (
[fooA] => a3
[fooB] => b3
[fooC] => c3
)
);