Question

How can I make two arrays correspond with each other?

For instance, this the 1st-months array I generated,

Array
(
    [0] => Sep
    [1] => Oct
    [2] => Nov
    [3] => Dec
    [4] => Jan
    [5] => Feb
    [6] => Mar
    [7] => Apr
    [8] => May
    [9] => Jun
    [10] => Jul
    [11] => Aug
)

And this is the 2nd-months array,

Array
(
    [0] => Sep
    [1] => May
    [2] => Apr
)

But I want the 2nd-months array to follow the same order as the 1st-months array, to return this as the result,

Array
(
    [0] => Sep
    [1] => Apr
    [2] => May
)

Is it possible?

EDIT:

The code that I use to generate the month arrays above,

# Set month array for the calendar and for the items.
$months_calender = array();
$months_items = array();

# Set variable for requested month/year.
$requested_year = set_variable($_REQUEST,'year');
$requested_month = set_variable($_REQUEST,'month');

# Set current month and curren year.
$current_month = (int)date('m');
$current_year = (int)date('Y');

# Loop the 12 month and starts from the current month.
for($x = $current_month; $x < $current_month+12; $x++) $months_calender[] = date('M', mktime(0, 0, 0, $x, 1));
print_r($months_calender); 
//echo $current_year;

# Check if the requested by $_REQUEST does not exit then use the current month/year as the requested month/year.
$requested_year = $requested_year? $requested_year : $current_year;
$requested_month = $requested_month? $requested_month : date('m', mktime(0, 0, 0, $current_month, 1));
//var_dump($requested_year);
//echo $requested_month;

# Use the stored connection object from the class_page_controller.php, to process the query
$items_monthly = $connection->fetch_all($sql_items_monthly,array($requested_year));
$total_items_monthly = $connection->num_rows($sql_items_monthly,array($requested_year));
//print_r($items_monthly);

# Check if the total items is more than 0, then loop the result to make an 1-d array.
if($total_items_monthly > 0) foreach($items_monthly as $item_monthly) $months_items[] = $item_monthly['archiveMonth'];
print_r($months_items);

the sql,

$sql_items_monthly = "
    SELECT 
    DATE_FORMAT(p.pg_backdate, '%b') AS archiveMonth,
    COUNT(p.pg_backdate)

    FROM root_pages AS p
    WHERE DATE_FORMAT(p.pg_backdate, '%Y') = ?
    AND p.cat_id = '2'
    AND p.parent_id = '6'
    AND p.pg_hide != '1'

    GROUP BY archiveMonth
    ORDER BY p.pg_backdate DESC
";

EDIT:

It seems I can get the result by this,

$result = array_intersect($months_calender, $months_items);
print_r($result);

returns,

Array
(
    [0] => Sep
    [7] => Apr
    [8] => May
)

Even though the keys are not started from 0 to 2 but it does not matter. Unless you have a better solution.

Answer 1

A simple combination of array_intersect and ksort will do the trick:

$array2 = array_intersect($array1, $array2);
ksort($array2);

See it in action.

If for some reason you want to have consecutive integer keys after this, it’s also easy to reindex the resulting array:

$array2 = array_values($array2);