Combine days where opening hours are similar

Question

How might I code a function in PHP (with CodeIgniter) to merge days with similar opening hours of a store together. For example, if we have:

Mon 9am-5pm
Tue          


        

Answer 1

 '9am-5pm',
    'Tue' => '9am-5pm',
    'Wed' => '9am-9pm',
    'Thu' => '9am-5pm',
    'Fri' => '9am-5pm',
    'Sat' => '9am-7pm',
    'Sun' => '9am-7pm'
);

$summaries = array();
foreach ($openHours as $day => $hours) {
    if (count($summaries) === 0) {
        $current = false;
    } else {
        $current = &$summaries[count($summaries) - 1];
    }
    if ($current === false || $current['hours'] !== $hours) {
        $summaries[] = array('hours' => $hours, 'days' => array($day));
    } else {
        $current['days'][] = $day;
    }
}

foreach ($summaries as $summary) {
    if (count($summary['days']) === 1) {
        echo reset($summary['days']) . ' ' . $summary['hours'] . PHP_EOL;
    } else {
        echo reset($summary['days']) . '-' . end($summary['days']) . ' ' . $summary['hours'] . PHP_EOL;
    }
}

codepad sample