I have an array like this:
[
[
'id' => 13,
'children' => [
['id' => 14, 'parent_id' => 13],
['id' => 15, 'parent_id' => 13],
]
]
]
How can I get all [id] values from this array and store them in a flat array like this:
[13, 14, 15]
$a is your original array.
array_merge(array($a['id']),
array_map(function($child) { return $child['id']; }, $a['children']));
If you use a recursive approach, it won't matter how long or how deep your array is. array_walk_recursive() will visit every "leafnode" in the array; if the key to that leafnode is id, then push the value into the result array.
Code: (Demo)
$result = [];
array_walk_recursive(
$array,
function($v, $k) use(&$result) {
if ($k === 'id') {
$result[] = $v;
}
}
);
var_export($result);
Related
In PHP, array_replace_recursive() does two things according to the documentation:
If a key from the first array exists in the second array, its value will be replaced by the value from the second array.
If the key exists in the second array, and not the first, it will be created in the first array.
Is there an alternative that only does the replacement, and doesn't create new keys?
For example:
$array = [
'apple' => TRUE,
'pear' => TRUE,
'basket' => [
'banana' => TRUE,
],
'punnet' => [
'strawberry' => TRUE,
],
];
$replacement = [
'banana' => [
'REPLACEMENT!'
],
];
The result should be:
$array = [
'apple' => TRUE,
'pear' => TRUE,
'basket' => [
'banana' => [
'REPLACEMENT!'
],
],
'punnet' => [
'strawberry' => TRUE,
],
];
You will need to use array_intersect_key() to create an array that contains only the keys that are in the two arrays, then you can merge.
$array1 = [
'a' => 1,
'b' => 2,
'c' => 3,
'd' => 4,
];
$array2 = [
'b' => 14,
'c' => 70,
'f' => 5,
];
// $array2 has to be the first arguments for $inter to have its value instead of the value of $array1
$inter = array_intersect_key($array2, $array1);
$merged = array_replace_recursive($array1, $inter);
// Merged will be:
[
'a' => 1,
'b' => 14,
'c' => 70,
'd' => 4,
];
array_intersect_key
EDIT
For this to work recursively, you can use this function found here
/**
* Recursively computes the intersection of arrays using keys for comparison.
*
* #param array $array1 The array with master keys to check.
* #param array $array2 An array to compare keys against.
* #return array associative array containing all the entries of array1 which have keys that are present in array2.
**/
function array_intersect_key_recursive(array $array1, array $array2) {
$array1 = array_intersect_key($array1, $array2);
foreach ($array1 as $key => &$value) {
if (is_array($value) && is_array($array2[$key])) {
$value = array_intersect_key_recursive($value, $array2[$key]);
}
}
return $array1;
}
If you don't like creation of non existant keys, you can use array_replace_recursive() as is and then you can roll out your own recursive version which would remove all extra keys. You may however roll out your own recursive replace version instead of the below 2 pass solution, but I would prefer the below described to avoid re-inventing the wheel of array_replace_recursive()(since you know what the wheel is about).
function removeNonExistantKeys(&$basket,&$base){
$keys = array_diff_key($basket, $base);
foreach($keys as $unwanted_key => $value){
unset($basket[ $unwanted_key ]);
}
foreach($basket as $key => &$value){
if(is_array($value) && is_array( $base[ $key ] )){
removeNonExistantKeys($value , $base[ $key ]);
}
}
}
We use & references wherever needed to edit the same copy of the array.
The above function uses array_diff_key to find difference between 2 sets of array in terms of keys and unsets all of them in the next foreach.
We then walk recursively to both modified and initial arrays into it's sub children performing the same task.
Driver code:
<?php
$base = array('citrus' => array( "orange") , 'berries' => array("blackberry", "raspberry"),'a' => ['b' => 'f']);
$replacements = array('citrus' => array('pineapple'), 'berries' => array('blueberry'),'a' => ['b' => 'd','e' => 'ab']);
$basket = array_replace_recursive($base, $replacements);
function removeNonExistantKeys(&$basket,&$base){
$keys = array_diff_key($basket, $base);
foreach($keys as $unwanted_key => $value){
unset($basket[ $unwanted_key ]);
}
foreach($basket as $key => &$value){
if(is_array($value) && is_array( $base[ $key ] )){
removeNonExistantKeys($value , $base[ $key ]);
}
}
}
removeNonExistantKeys($basket,$base);
print_r($basket);
This does what I needed:
array_walk_recursive($array, function(&$value, $key, $replacements) {
if (isset($replacements[$key])) {
$value = $replacements[$key];
}
}, ['replace' => 'replacement']);
I have these 2 arrays.
First array is from user input $cart:
$cart = [
['id' => 3, 'weight' => 20, 'percentage' => 80],
['id' => 1, 'weight' => 50, 'percentage' => 80],
['id' => 2, 'weight' => 40, 'percentage' => 80],
];
and second array, I do a database SELECT id, stock WHERE id IN (3,1,2), resulting $db_item
$db_item = [
['id' => 1, 'stock' => 9539.00],
['id' => 2, 'stock' => 9468.00],
['id' => 3, 'stock' => 9295.00],
];
I want to add the stock attribute in second array to first array.
Expected output:
$cart = [
['id' => 3, 'weight' => 20, 'percentage' => 80, 'stock' => 9295.00],
['id' => 1, 'weight' => 50, 'percentage' => 80, 'stock' => 9539.00],
['id' => 2, 'weight' => 40, 'percentage' => 80, 'stock' => 9468.00],
];
This is what I tried, and it works, but I don't think it is necessary to have foreach, array_filter, and array_column:
foreach ($cart as $key => $cart_item) {
$item = array_filter($db_item, function($item) use ($cart_item) {
return $item['id'] === $cart_item['id'];
});
$cart[$key]['stock'] = array_column($item, 'stock')[0];
}
anyone has better idea how to optimize this?
EDIT: following Mohammad's answer, I can use more attribute in second array
$keys = [];
foreach ($arr2 as $item) {
$keys[$item['id']] = array(
'attr1' => $item['attr1'],
'attr2' => $item['attr2'],
// and so on
);
}
$newArr = array_map(function($item) use($keys){
$item['attr1'] = $keys[$item['id']]['attr1'];
$item['attr2'] = $keys[$item['id']]['attr2'];
// and so on
return $item;
}, $arr1);
EDIT2: found out that we can simplify the foreach loop with just a single line using array_column.
$keys = array_column($arr2, null, 'id');
$newArr = array_map(function($item) use($keys){
$item['attr1'] = $keys[$item['id']]['attr1'];
$item['attr2'] = $keys[$item['id']]['attr2'];
// and so on
return $item;
}, $arr1);
Use combination of array_flip() and array_column() to create array contain id and index of second array.
Then use array_map() to add new key stock to first array.
$keys = array_flip(array_column($arr2, 'id'));
$newArr = array_map(function($item) use($keys, $arr2){
$item['stock'] = $arr2[$keys[$item['id']]]['stock'];
return $item;
}, $arr1);
Check result in demo
Also you can use foreach instead of array_flip()
$keys = [];
foreach ($arr2 as $item)
$keys[$item['id']] = $item['stock'];
$newArr = array_map(function($item) use($keys){
$item['stock'] = $keys[$item['id']];
return $item;
}, $arr1);
Check result in demo
This can help too, one array_column + one array_map :
$arr2=array_column($arr2,'stock','id');
$arr1=array_map(function($val)use($arr2){$val['stock']=$arr2[$val['id']];return $val;},$arr1);
I have the next array
[
['id' => 30, 'count' => 3],
['id' => 45, 'count' => 7]
]
I need it to be
[
30 => ['count' => 3],
45 => ['count' => 7]
]
What I did
$formatted = [];
foreach ($services as $service) {
$formatted[$service['id']] = [
'count' => $service['count']
];
}
What I'd like is a more elegant solution without the temporary $formatted variable. Thanks!
Update. Thanks a lot #rtrigoso !
With the laravel collection, my code looks next
$services->reduce(function ($carry, $item) {
$carry[$item['id']] = ['count' => $item['count']];
return $carry;
});
You can do this in one line with array_column:
$array = array_column($array, null, 'id');
The one difference between your desired output is that this will still contain the id key in the second level of the array, like so:
[
30 => ['id' => 30, 'count' => 3],
45 => ['id' => 45, 'count' => 7],
]
but that hopefully shouldn't cause any problems. If you do need to remove it, you can do it with something like:
$array = array_map(function ($e) {
unset($e['id']);
return $e;
}, $array);
This approach is probably best if your rows could potentially have a lot more keys in them in future, i.e. it's quicker to list the keys to remove rather than the ones to keep. If not, and you'll only have a count, then to be honest your original example is probably the best you'll get.
You can use array_reduce
$x_arr = array(
array('id' => 30, 'count' => 3),
array('id' => 45, 'count' => 7),
);
$y_arr = array_reduce($x_arr, function ($result, $item) {
$result[$item['id']] = array('count' => $item['count']);
return $result;
}, array());
print_r($y_arr);
It will give you your desired result:
Array
(
[30] => Array
(
[count] => 3
)
[45] => Array
(
[count] => 7
)
)
I have this initial array:
[
0 => ['id' => 5, 'value' => 50],
1 => ['id' => 6, 'value' => 60],
2 => ['id' => 7, 'value' => 70],
]
and want to convert it to:
[
5 => ['value' => 50],
6 => ['value' => 60],
7 => ['value' => 70],
]
At first, I tried to use map, but it can't modify the array keys, so I thought reduce would solve the problem because it reduces the array to a single value, in this case, an array. So I tried:
array_reduce(
$array,
function($carry, $item) {
return $carry[$item['id']] = $item['value'];
},
[]
);
But it returns this error Cannot use a scalar value as an array. What am I doing wrong? Does array_reduce cannot receive an array as an initial value?
Your array_reduce didn't work because You weren't returning the accumulator array (carry in Your case) from the callback function.
array_reduce(
$array,
function($carry, $item) {
$carry[$item['id']] = $item['value'];
return $carry; // this is the only line I added :)
},
[]
);
I came to this question while looking for a way to use array_reduce, so I felt I should write this comment. I hope this will help future readers. :)
As Mark Bakerdid it. I also did with foreach loop.
$arr = array(
array('id' => 5, 'value' => 50),
array('id' => 6, 'value' => 60),
array('id' => 7, 'value' => 70)
);
$result = array();
$result = array_column($arr, 'value', 'id');
array_walk($result, function(&$value) { $value = ['value' => $value]; });
//I did this using foreach loop, But the OP need it through array function.
//foreach($arr as $key => $value){
// $result[$value['id']] = array('value' => $value['value']);
//}
echo '<pre>';
print_r($result);
Result:
Array
(
[5] => Array
(
[value] => 50
)
[6] => Array
(
[value] => 60
)
[7] => Array
(
[value] => 70
)
)
Sometimes the best solutions are the simplest. Loop through your array and assign the id and value to a new array.
$new_array = array();
foreach ($array as $key => $arr) {
$new_array[$arr['id']] = array('value' => $arr['value']);
}
You can do it functionally. I suspect it's not actually more readable however.
array_combine(
array_column($a, 'id'),
array_map(function($v) { return ['value' => $v['value']]; }, $a)
);
Or even...
array_map(
function($v) { return ['value' => $v['value']]; },
array_column($a, null, 'id')
)
array_reduce($ar, function ($acc, $item) {
$acc[$item['id']] = [ 'value' => $item['value']];
return $acc;
}, [])
I have an array:
$array = [
'foo' => 44,
'bar' => 77,
'moo' => 88,
];
Now I have two variables, $key and $value, and I want to replace the first index of the array. So remove foo and 44, and add $key and $value in their place.
So my array becomes:
$array = [
$key => $foo,
'bar' => 77,
'moo' => 88,
];
How may I do this?
Remove the first element of the array:
array_shift($array);
Add the new key/value pair to the start of the array:
$array = array($key => $value) + $array;