Get Array Values Recursively with PHP
I've been helping to write a WordPress plugin (I'm not ready to share it yet) and one of the tasks required is validating an array of user-selected values against a list of known valid values. The known valid array is actually a key=>value array so unfortunately array_values wont help get the simple list I'd like.
Instead a more advanced custom function was needed:
// http://php.net/manual/en/function.array-values.php
function array_values_recursive($array) {
$flat = array();
foreach($array as $value) {
if (is_array($value)) {
$flat = array_merge($flat, array_values_recursive($value));
}
else {
$flat[] = $value;
}
}
return $flat;
}
This recursive function dives into arrays, even key=>value arrays, to retrieve the final list of values. Thank you PHP.net!
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No need to create a new array, just use iterators. There is an interface for iterators with values that can be iterators called RecursiveIterator. To wrap a nested array there is RecursiveArrayIterator. And to flatten an RecursiveIterator you can use RecursiveIteratorIterator, which by default only returns the leaves.
$it = new RecursiveIteratorIterator(new RecursiveArrayIterator($array)); foreach ($it as $k => $v) { var_dump("$k = $v"); }If you want to convert it to an array use iterator_to_array():
Although if you’re going to call
iterator_to_array()I think you’ve defeated your stated purpose for using iterators.function flatten_array($arg) { return is_array($arg) ? array_reduce($arg, function ($c, $a) { return array_merge($c, flatten_array($a)); },[]) : [$arg]; }