Changing value inside foreach loop doesn't change value in the array being iterated over

Question

Why does this yield this:

foreach( $store as $key => $value){
$value = $value.".txt.gz";
}

unset($value);

print_r ($store);

Array
(
[1] => 101Phones - Product Catalog TXT
[2] => 1-800-FLORALS - Product Catalog 1
)

I am trying to get 101Phones - Product Catalog TXT.txt.gz

Thoughts on whats going on?

EDIT: Alright I found the solution...my variables in my array had values I couldn't see...doing

$output = preg_replace('/[^(\x20-\x7F)]*/','', $output);
echo($output);

Cleaned it up and made it work properly

Answer 1

The $value variable in the array is temporary, it does not refer to the entry in the array.
If you want to change the original array entry, use a reference:

foreach ($store as $key => &$value) {
                       //  ^ reference
    $value .= '.txt.gz';
}