Related
I have two array
First
array(
0 => 100000,
1 => 50000,
2 => 100000,
3 => 100000);
Second
array(
0 => 150000,
1 => 200000,);
The problem is I want to get the combination from first array that formed each second array.
Example
Second array index 0 can be formed from first array index 0 and 1 and second array index 1 can be formed from first array index 2 and 3
I want to achieve like this
[0 => [0,1] , 1 => [2,3]]
Thanks for the help.
A simple an fast gready approach would be to first sort the arrays descending. After that, loop over the second one and collect from the first one as much values, till you reach your desired value.
$first = [
0 => 100000,
1 => 50000,
2 => 100000,
3 => 100000
];
$second = [
0 => 150000,
1 => 200000
];
arsort($first);
arsort($second);
$combinations = [];
foreach ($second as $search) {
$combination = [];
$sum = 0;
foreach ($first as $key => $val) {
if ($sum + $val > $search) continue;
$sum += $val;
$combination[] = $key;
if ($sum == $search) break;
}
if ($sum != $search) die("nothing found this way..");
foreach ($combination as $val) unset($first[$val]);
$combinations[] = $combination;
}
print_r($combinations);
Here is the simple idea to achieve your requirement. There would be many if's and but you need to consider yourself
<?php
$arr1 = [0 => 100000,1 => 50000,2 => 100000,3 => 100000];
$arr2 = [0 => 150000,1 => 200000];
//$arr2 = [0 => 250000,1 => 100000];
$count = 0;
$new = array();
for($i=0;$i<count($arr1);$i++){
if($arr1[$i] == $arr2[$count]){
$new[$arr2[$count]] = $arr1[$i];
$count++;
}else{
$sum = [$arr1[$i]];
for($j=$i+1;$j<count($arr1);$j++){
$sum[] = $arr1[$j];
if( array_sum($sum) == $arr2[$count]){
$new[$arr2[$count]] = $sum;
$count++;
}
}
}
}
print_r($new);
?>
Output1
Output2
Try with following code:
$arr = array(
0 => 100000,
1 => 50000,
2 => 100000,
3 => 100000);
$count = $val = 0;
$newArr = [];
foreach($arr as $a){
$val += $a;
$count++;
if($count == 2){
$newArr[] = $val;
$val = $count = 0;
}
}
print_r($newArr); die;
I want to split an array in 2 pieces and add the first slice to the end. The point where it should splitten is set in another variable.
$where = 7;
$array = array( 1 => "aaa", 2 => "bbb", 7 => "ccc", 13 => "ddd", 20 => "eee" );
//...code...
//I'd like to have
$array = array(7 => "ccc", 13 => "ddd", 20 => "eee", 1 => "aaa", 2 => "bbb" );
How to achieve that?
foreach($array as $key=>$value)
{
if ($key === $where)
{
break;
}
unset($array[$key]);
$array[$key] = $value;
}
You can use array_slice() to split the array twice -->
$arr1 = array_slice($array, 0, $where-1);
$arr2 = array_slice($array, $where, count($array)-1);
$array = array();
$array[] = $arr2;
$array[] = $arr1;
function split_array($array, $where) {
$temp_array = array();
foreach ($array as $key => $value) {
if($key != $where) {
$temp_array[$key] = $value;
unset($array[$key]);
}
else {
break;
}
}
//return array_merge($array, $temp_array);
return ($array+$temp_array);
}
You can use array_slice() with a offset to split the array, and join the two chunks with the array union operator.
$where = 7;
$array = array( 1 => "aaa", 2 => "bbb", 7 => "ccc", 13 => "ddd", 20 => "eee" );
$offset = array_search($where, array_keys($array), true);
if ($offset !== false) {
$array = array_slice($array, $offset, null, true) + $array;
}
How can I search for a key in an array that contains more arrays.
For example I would like to search for "key" in "arr" and return this:
arr["some_inner_array"]["another_array_possible"][key"]
array_key_exists can tell me if it exists, but of course what I really need in the value...
I hope my question is clear...
EDIT:
based on the answer below, I managed to do a recursive function for that:
function look_in_array ( $array, $key ) {
if ( isset($array[$key]) )
return $array[$key];
foreach ($array as $item) {
if (is_array($item)) {
$value = look_in_array ($item,$key);
if ($value)
return $value;
}
}
}
This function should work:
function array_key_exists_recursive($searchKey, $array)
{
$result = false;
foreach($array as $key => $value)
{
if(is_array($array[$key]))
{
$result = array_key_exists_recursive($searchKey, $array[$key]);
}
else if(array_key_exists($searchKey, $array))
{
$result = $array[$searchKey];
}
if($result)
break;
}
return $result;
}
Exmaple:
$array = array( "a" => array("b" => "1", "c" => "2") );
var_dump(array_key_exists_recursive("c", $array)); //Result: 2
You could just ask this:
isset(arr["some_inner_array"]["another_array_possible"]["key"])
Would this work for you? Otherwise maybe explaning a bit better about what you're trying to accomplish would help us help you :)
You need to iterate over all elements in the first arrays and then use array_key_exists():
foreach($arr as $inner1) {
foreach($inner1 as $inner2) {
if array_key_exists($inner2, $key) {
echo $inner2[$key];
break 2; // if you only want the first match
}
}
}
Try this:
/**
* #param $path array containing path
* #param $array search array
* #return element matching path or null
*/
function arr_search($path, &$array){
$tmp = &$array;
for($i = 0; $i < count($path); $i++){
if(!isset($tmp[$path[$i]])) return null;
$tmp = &$tmp[$path[$i]];
}
return $tmp;
}
$arr = array(
'a' => array(
'b' => array(
'c' => 'abc',
),
'd' => array('ad'),
),
10 => array(100, 200, 300),
);
var_dump(arr_search(array('a', 'b', 'c'), $arr));
var_dump(arr_search(array('a', 'd'), $arr));
var_dump(arr_search(array(10, 100), $arr));
var_dump(arr_search(array(10, 1), $arr));
// EDIT previous example was wrong, so here is new one :)
function arr_search($key, $array){
$values = array();
if(array_key_exists($key, $array)) $values[] = $array[$key];
$stack = array_values($array);
while($tmp = array_pop($stack)){
if(is_array($tmp)){
foreach($tmp as &$v){
array_push($stack, $v);
}
if(array_key_exists($key, $tmp)){
$values[] = $tmp[$key];
}
}
}
return $values;
}
$arr = array(
'a' => array(
'b' => array(
'c' => 'abc',
),
'd' => array('ad'),
),
'e' => array(
'a' => array(
'b' => 'abc',
),
'b' => array('xyz'),
),
10 => array(100, 200, 300),
);
var_dump(arr_search('b', $arr));
var_dump(arr_search(0, $arr));
Example:
$arr = array(
'apple' => 'sweet',
'grapefruit' => 'bitter',
'pear' => 'tasty',
'banana' => 'yellow'
);
I want to switch the positions of grapefruit and pear, so the array will become
$arr = array(
'apple' => 'sweet',
'pear' => 'tasty',
'grapefruit' => 'bitter',
'banana' => 'yellow'
)
I know the keys and values of the elements I want to switch, is there an easy way to do this? Or will it require a loop + creating a new array?
Thanks
Just a little shorter and less complicated than the solution of arcaneerudite:
<?php
if(!function_exists('array_swap_assoc')) {
function array_swap_assoc($key1, $key2, $array) {
$newArray = array ();
foreach ($array as $key => $value) {
if ($key == $key1) {
$newArray[$key2] = $array[$key2];
} elseif ($key == $key2) {
$newArray[$key1] = $array[$key1];
} else {
$newArray[$key] = $value;
}
}
return $newArray;
}
}
$array = $arrOrig = array(
'fruit' => 'pear',
'veg' => 'cucumber',
'tuber' => 'potato',
'meat' => 'ham'
);
$newArray = array_swap_assoc('veg', 'tuber', $array);
var_dump($array, $newArray);
?>
Tested and works fine
Here's my version of the swap function:
function array_swap_assoc(&$array,$k1,$k2) {
if($k1 === $k2) return; // Nothing to do
$keys = array_keys($array);
$p1 = array_search($k1, $keys);
if($p1 === FALSE) return; // Sanity check...keys must exist
$p2 = array_search($k2, $keys);
if($p2 === FALSE) return;
$keys[$p1] = $k2; // Swap the keys
$keys[$p2] = $k1;
$values = array_values($array);
// Swap the values
list($values[$p1],$values[$p2]) = array($values[$p2],$values[$p1]);
$array = array_combine($keys, $values);
}
if the array comes from the db, add a sort_order field so you can always be sure in what order the elements are in the array.
This may or may not be an option depending on your particular use-case, but if you initialize your array with null values with the appropriate keys before populating it with data, you can set the values in any order and the original key-order will be maintained. So instead of swapping elements, you can prevent the need to swap them entirely:
$arr = array('apple' => null,
'pear' => null,
'grapefruit' => null,
'banana' => null);
...
$arr['apple'] = 'sweet';
$arr['grapefruit'] = 'bitter'; // set grapefruit before setting pear
$arr['pear'] = 'tasty';
$arr['banana'] = 'yellow';
print_r($arr);
>>> Array
(
[apple] => sweet
[pear] => tasty
[grapefruit] => bitter
[banana] => yellow
)
Not entirely sure if this was mentioned, but, the reason this is tricky is because it's non-indexed.
Let's take:
$arrOrig = array(
'fruit'=>'pear',
'veg'=>'cucumber',
'tuber'=>'potato'
);
Get the keys:
$arrKeys = array_keys($arrOrig);
print_r($arrKeys);
Array(
[0]=>fruit
[1]=>veg
[2]=>tuber
)
Get the values:
$arrVals = array_values($arrOrig);
print_r($arrVals);
Array(
[0]=>pear
[1]=>cucumber
[2]=>potato
)
Now you've got 2 arrays that are numerical. Swap the indices of the ones you want to swap, then read the other array back in in the order of the modified numerical array. Let's say we want to swap 'fruit' and 'veg':
$arrKeysFlipped = array_flip($arrKeys);
print_r($arrKeysFlipped);
Array (
[fruit]=>0
[veg]=>1
[tuber]=>2
)
$indexFruit = $arrKeysFlipped['fruit'];
$indexVeg = $arrKeysFlipped['veg'];
$arrKeysFlipped['veg'] = $indexFruit;
$arrKeysFlipped['fruit'] = $indexVeg;
print_r($arrKeysFlipped);
Array (
[fruit]=>1
[veg]=>0
[tuber]=>2
)
Now, you can swap back the array:
$arrKeys = array_flip($arrKeysFlipped);
print_r($arrKeys);
Array (
[0]=>veg
[1]=>fruit
[2]=>tuber
)
Now, you can build an array by going through the oringal array in the 'order' of the rearranged keys.
$arrNew = array ();
foreach($arrKeys as $index=>$key) {
$arrNew[$key] = $arrOrig[$key];
}
print_r($arrNew);
Array (
[veg]=>cucumber
[fruit]=>pear
[tuber]=>potato
)
I haven't tested this - but this is what I'd expect. Does this at least provide any kind of help? Good luck :)
You could put this into a function $arrNew = array_swap_assoc($key1,$key2,$arrOld);
<?php
if(!function_exists('array_swap_assoc')) {
function array_swap_assoc($key1='',$key2='',$arrOld=array()) {
$arrNew = array ();
if(is_array($arrOld) && count($arrOld) > 0) {
$arrKeys = array_keys($arrOld);
$arrFlip = array_flip($arrKeys);
$indexA = $arrFlip[$key1];
$indexB = $arrFlip[$key2];
$arrFlip[$key1]=$indexB;
$arrFlip[$key2]=$indexA;
$arrKeys = array_flip($arrFlip);
foreach($arrKeys as $index=>$key) {
$arrNew[$key] = $arrOld[$key];
}
} else {
$arrNew = $arrOld;
}
return $arrNew;
}
}
?>
WARNING: Please test and debug this before just using it - no testing has been done at all.
There is no easy way, just a loop or a new array definition.
Classical associative array doesn't define or guarantee sequence of elements in any way. There is plain array/vector for that. If you use associative array you are assumed to need random access but not sequential. For me you are using assoc array for task it is not made for.
yeah I agree with Lex, if you are using an associative array to hold data, why not using your logic handle how they are accessed instead of depending on how they are arranged in the array.
If you really wanted to make sure they were in a correct order, trying creating fruit objects and then put them in a normal array.
There is no easy way to do this. This sounds like a slight design-logic error on your part which has lead you to try to do this when there is a better way to do whatever it is you are wanting to do. Can you tell us why you want to do this?
You say that I know the keys and values of the elements I want to switch which makes me think that what you really want is a sorting function since you can easily access the proper elements anytime you want as they are.
$value = $array[$key];
If that is the case then I would use sort(), ksort() or one of the many other sorting functions to get the array how you want. You can even use usort() to Sort an array by values using a user-defined comparison function.
Other than that you can use array_replace() if you ever need to swap values or keys.
Here are two solutions. The first is longer, but doesn't create a temporary array, so it saves memory. The second probably runs faster, but uses more memory:
function swap1(array &$a, $key1, $key2)
{
if (!array_key_exists($key1, $a) || !array_key_exists($key2, $a) || $key1 == $key2) return false;
$after = array();
while (list($key, $val) = each($a))
{
if ($key1 == $key)
{
break;
}
else if ($key2 == $key)
{
$tmp = $key1;
$key1 = $key2;
$key2 = $tmp;
break;
}
}
$val1 = $a[$key1];
$val2 = $a[$key2];
while (list($key, $val) = each($a))
{
if ($key == $key2)
$after[$key1] = $val1;
else
$after[$key] = $val;
unset($a[$key]);
}
unset($a[$key1]);
$a[$key2] = $val2;
while (list($key, $val) = each($after))
{
$a[$key] = $val;
unset($after[$key]);
}
return true;
}
function swap2(array &$a, $key1, $key2)
{
if (!array_key_exists($key1, $a) || !array_key_exists($key2, $a) || $key1 == $key2) return false;
$swapped = array();
foreach ($a as $key => $val)
{
if ($key == $key1)
$swapped[$key2] = $a[$key2];
else if ($key == $key2)
$swapped[$key1] = $a[$key1];
else
$swapped[$key] = $val;
}
$a = $swapped;
return true;
}
fwiw here is a function to swap two adjacent items to implement moveUp() or moveDown() in an associative array without foreach()
/**
* #param array $array to modify
* #param string $key key to move
* #param int $direction +1 for down | -1 for up
* #return $array
*/
protected function moveInArray($array, $key, $direction = 1)
{
if (empty($array)) {
return $array;
}
$keys = array_keys($array);
$index = array_search($key, $keys);
if ($index === false) {
return $array; // not found
}
if ($direction < 0) {
$index--;
}
if ($index < 0 || $index >= count($array) - 1) {
return $array; // at the edge: cannot move
}
$a = $keys[$index];
$b = $keys[$index + 1];
$result = array_slice($array, 0, $index, true);
$result[$b] = $array[$b];
$result[$a] = $array[$a];
return array_merge($result, array_slice($array, $index + 2, null, true));
}
There is an easy way:
$sourceArray = array(
'apple' => 'sweet',
'grapefruit' => 'bitter',
'pear' => 'tasty',
'banana' => 'yellow'
);
// set new order
$orderArray = array(
'apple' => '', //this values would be replaced
'pear' => '',
'grapefruit' => '',
//it is not necessary to touch all elemets that will remains the same
);
$result = array_replace($orderArray, $sourceArray);
print_r($result);
and you get:
$result = array(
'apple' => 'sweet',
'pear' => 'tasty',
'grapefruit' => 'bitter',
'banana' => 'yellow'
)
function arr_swap_keys(array &$arr, $key1, $key2, $f_swap_vals=false) {
// if f_swap_vals is false, then
// swap only the keys, keeping the original values in their original place
// ( i.e. do not preserve the key value correspondence )
// i.e. if arr is (originally)
// [ 'dog' => 'alpha', 'cat' => 'beta', 'horse' => 'gamma' ]
// then calling this on arr with, e.g. key1 = 'cat', and key2 = 'horse'
// will result in arr becoming:
// [ 'dog' => 'alpha', 'horse' => 'beta', 'cat' => 'gamma' ]
//
// if f_swap_vals is true, then preserve the key value correspondence
// i.e. in the above example, arr will become:
// [ 'dog' => 'alpha', 'horse' => 'gamma', 'cat' => 'beta' ]
//
//
$arr_vals = array_values($arr); // is a (numerical) index to value mapping
$arr_keys = array_keys($arr); // is a (numerical) index to key mapping
$arr_key2idx = array_flip($arr_keys);
$idx1 = $arr_key2idx[$key1];
$idx2 = $arr_key2idx[$key2];
swap($arr_keys[$idx1], $arr_keys[$idx2]);
if ( $f_swap_vals ) {
swap($arr_vals[$idx1], $arr_vals[$idx2]);
}
$arr = array_combine($arr_keys, $arr_vals);
}
function swap(&$a, &$b) {
$t = $a;
$a = $b;
$b = $t;
}
Well it's just a key sorting problem. We can use uksort for this purpose. It needs a key comparison function and we only need to know that it should return 0 to leave keys position untouched and something other than 0 to move key up or down.
Notice that it will only work if your keys you want to swap are next to each other.
<?php
$arr = array(
'apple' => 'sweet',
'grapefruit' => 'bitter',
'pear' => 'tasty',
'banana' => 'yellow'
);
uksort(
$arr,
function ($k1, $k2) {
if ($k1 == 'grapefruit' && $k2 == 'pear') return 1;
else return 0;
}
);
var_dump($arr);
I'll share my short version too, it works with both numeric and associative arrays.
array array_swap ( array $array , mixed $key1 , mixed $key2 [, bool $preserve_keys = FALSE [, bool $strict = FALSE ]] )
Returns a new array with the two elements swapped. It preserve original keys if specified. Return FALSE if keys are not found.
function array_swap(array $array, $key1, $key2, $preserve_keys = false, $strict = false) {
$keys = array_keys($array);
if(!array_key_exists($key1, $array) || !array_key_exists($key2, $array)) return false;
if(($index1 = array_search($key1, $keys, $strict)) === false) return false;
if(($index2 = array_search($key2, $keys, $strict)) === false) return false;
if(!$preserve_keys) list($keys[$index1], $keys[$index2]) = array($key2, $key1);
list($array[$key1], $array[$key2]) = array($array[$key2], $array[$key1]);
return array_combine($keys, array_values($array));
}
For example:
$arr = array_swap($arr, 'grapefruit', 'pear');
I wrote a function with more general purpose, with this problem in mind.
array with known keys
specify order of keys in a second array ($order array keys indicate key position)
function order_array($array, $order) {
foreach (array_keys($array) as $k => $v) {
$keys[++$k] = $v;
}
for ($i = 1; $i <= count($array); $i++) {
if (isset($order[$i])) {
unset($keys[array_search($order[$i], $keys)]);
}
if ($i === count($array)) {
array_push($keys, $order[$i]);
} else {
array_splice($keys, $i-1, 0, $order[$i]);
}
}
}
foreach ($keys as $key) {
$result[$key] = $array[$key];
}
return $result;
} else {
return false;
}
}
$order = array(1 => 'item3', 2 => 'item5');
$array = array("item1" => 'val1', "item2" => 'val2', "item3" => 'val3', "item4" => 'val4', "item5" => 'val5');
print_r($array); -> Array ( [item1] => val1 [item2] => val2 [item3] => val3 [item4] => val4 [item5] => val5 )
print_r(order_array($array, $order)); -> Array ( [item3] => val3 [item5] => val5 [item1] => val1 [item2] => val2 [item4] => val4 )
I hope this is relevant / helpful for someone
Arrays in php are ordered maps.
$arr = array('apple'=>'sweet','grapefruit'=>'bitter','
pear'=>'tasty','banana'=>'yellow');
doesn't mean that that the first element is 'apple'=>'sweet' and the last - 'banana'=>'yellow' just because you put 'apple' first and 'banana' last. Actually, 'apple'=>'sweet' will be the first and
'banana'=>'yellow' will be the second because of alphabetical ascending sort order.
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
)
);