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] => 101Phon         


        

Answer 1

foreach(array_container as & array_value)

Is the way to modify array element value inside foreach loop.

Answer 2

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';
}

Answer 3

pass $value as a reference:

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

Answer 4

Try

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

Answer 5

Try

$catalog = array();

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


print_r ($catalog);

OR

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


print_r ($store);

Depends on what you want to achieve

Thanks :)

Answer 6

The doc http://php.net/manual/en/control-structures.foreach.php clearly states why you have a problem:

"In order to be able to directly modify array elements within the loop precede $value with &. In that case the value will be assigned by reference."

<?php
$arr = array(1, 2, 3, 4);
foreach ($arr as &$value) {
    $value = $value * 2;
}
// $arr is now array(2, 4, 6, 8)
unset($value); // break the reference with the last element
?>

Referencing $value is only possible if the iterated array can be referenced (i.e. if it is a variable). The following code won't work:

<?php
/** this won't work **/
foreach (array(1, 2, 3, 4) as &$value) {
    $value = $value * 2;
}
?>