Question

Let’s say I have an array:

$myArray = array('alfa' => 'apple', 'bravo' => 'banana', 'charlie' => 'cherry', 'delta' => 'danjou pear');

I want to search it for certain keys and if found replace the values of those according to this other array:

$myReplacements = array('bravo' => 'bolognese', 'lie' => 'candy');

I know I can do this:

function array_search_replace($haystack, $replacements, $exactMatch = false) {
    foreach($haystack as $haystackKey => $haystackValue) {
        foreach($replacements as $replacementKey => $replacementValue) {
            if($haystackKey == $replacementKey || (!$exactMatch && strpos($haystackKey, $replacementKey) !== false)) {
                $haystack[$haystackKey] = $replacementValue;
            }
        }
    }
    return $haystack;
}

But, is there really no smarter/faster way to do it?

EDIT: I also need to be able to search for keyparts, so that ‘lie’ and ‘charlie’ results in a match.

EDIT2: Expected results are:

var_dump(array_search_replace($myArray, $myReplacements));

array(4) { ["alfa"]=> string(5) "apple" ["bravo"]=> string(9) "bolognese" ["charlie"]=> string(5) "candy" ["delta"]=> string(11) "danjou pear" }

var_dump(array_search_replace($myArray, $myReplacements, true));

array(4) { ["alfa"]=> string(5) "apple" ["bravo"]=> string(9) "bolognese" ["charlie"]=> string(6) "cherry" ["delta"]=> string(11) "danjou pear" }

Answer 1

Arrays in PHP are hashes, you don’t need to search for a key, you can access it in O(1) time.

$myArray = array('alfa' => 'apple', 'bravo' => 'banana', 'charlie' => 'cherry', 'delta' => 'danjou pear');
$myReplacements = array('bravo' => 'bolognese', 'lie' => 'candy');

var_dump($myArray);

foreach($myReplacements as $k => $v) {
  if(array_key_exists($k, $myArray)) {
    $myArray[$k] = $v;
  }
}

var_dump($myArray);

Output:

array(4) {
  ["alfa"]=>
  string(5) "apple"
  ["bravo"]=>
  string(6) "banana"
  ["charlie"]=>
  string(6) "cherry"
  ["delta"]=>
  string(11) "danjou pear"
}
array(4) {
  ["alfa"]=>
  string(5) "apple"
  ["bravo"]=>
  string(9) "bolognese"
  ["charlie"]=>
  string(6) "cherry"
  ["delta"]=>
  string(11) "danjou pear"
}