PHP Loop through multi-dimensional array into new array - php

Question

I have a PHP array like this...
[level1] => Array
(
[random475item] => Array
(
[attr1] => tester1
[attr2] => tester2
[attr3] => tester3
)
[random455item] => Array
(
[attr1] => tester1
[attr2] => tester2
[attr3] => tester3
)
)
I am trying to get the values of the attr2 fields in a new array. I can specify a specific like this...
$newarray = array();
newarray [] = $array['level1']['random475item']['attr2'];
newarray [] = $array['level1']['random455item']['attr2'];
But is there a way to automate this as it could be 50 random items coming up and I don't want to have to keep adding them manually.

Answer 1

https://www.php.net/manual/en/function.array-column.php and the code below at
https://3v4l.org/8j3ae
<?php
$array = ['level1' => [
'item1' => [
'attr1' => 'test1',
'attr2' => 'test2',
'attr3' => 'test3'
],
'item2' => [
'attr1' => 'test4',
'attr2' => 'test5',
'attr3' => 'test6'
],
]];
$values = array_column($array['level1'], 'attr2');
var_dump($values);
creates
array(2) {
[0]=>
string(5) "test2"
[1]=>
string(5) "test5"
}

Answer 2

You can use array_map for that :
$array = ['level1' => [
'item1' => [
'attr1' => 'test1',
'attr2' => 'test2',
'attr3' => 'test3'
],
'item2' => [
'attr1' => 'test4',
'attr2' => 'test5',
'attr3' => 'test6'
],
]];
// parse every item
$values = array_map(function($item) {
// for each item, return the value 'attr2'
return $item['attr2'];
}, $array['level1']);
I have created a sandbox for you to try;

Answer 3

Use foreach statement will be solved your case
$newarray = array();
foreach($array['level1'] as $randomItemKey => $randomItemValue){
$newarray[] = $randomItemValue['attr2'];
}

Answer 4

If the values can occur at any point in the array, you can use array_walk_recursive() which will loop through all of the values (only leaf nodes) and you can check if it is an attr2 element and add it into an output array...
$out = [];
array_walk_recursive($array, function ($data, $key ) use (&$out) {
if ( $key == "attr2" ) {
$out[] = $data;
}
});