Compare keys and values from 2 arrays and store same values - php

Question

I want to compare keys from one array against values from another array, and when a match is made to store the value from the first array (whose key matched the value in the second one).
With my code, it always echoes out 4. How can I modify it so that it echoes out 1 2 3 4?
The code:
$first = array('location', 'genre', 'studio', 'Lord_Of_the_Rings');
$second = array(
'location' => 1,
'genre' => 2,
'studio' => 3,
'Lord_Of_the_Rings' => 4
);
while ($el = current($second)) {
$d .= ','.key($second);
next($second);
}
$d = ltrim($d, ',');
$d = explode(',', $d);
foreach ($first as $the_tax) {
foreach ($d as $key => $v) {
if (in_array($v, $first)) {
$t = $second[$v];
}
}
echo $t.'<br>';
}

Answer 1

To be honsest, if you wouldn't explain your goal, I wouldn't even understand what you're trying to do by your code. Try like this:
<?php
$first = array('location', 'genre', 'studio', 'Lord_Of_the_Rings');
$second = array(
'location' => 1,
'genre' => 2,
'studio' => 3,
'Lord_Of_the_Rings' => 4
);
$intersect = array_intersect($first, array_keys($second));
foreach($intersect as $key)
echo $second[$key];
?>

Answer 2

You should move/add add an echo statement into the block where you assign the value of $t, maybe this way:
foreach ($first as $the_tax) {
foreach ($d as $key => $v) {
if (in_array($v, $first)) {
$t = $second[$v];
echo $t.' ';
}
}
echo '<br>';
}

Answer 3

you can flip the keys in second array, and then take the intersection of the 2. something along these lines
<?php
$first = array('location', 'genre', 'studio', 'Lord_Of_the_Rings');
$second = array(
'location' => 1,
'genre' => 2,
'studio' => 3,
'Lord_Of_the_Rings' => 4
);
$flipped = array_flip($second);
print implode(' ',array_keys(array_intersect($flipped, $first)));
?>