在PHP中计算和构造唯一数组的更好方法

Question

I have the following code which takes rediculously long time to execute. Sometimes it even times out.

foreach ($totalownerships as $totalownership) {
    if (!in_array($totalownership['titleno'], $totaltitles)) {
        $result['totalowns'] += 1;
        $totaltitles[] = $totalownership['titleno'];
        $result['ownershipid'] = $result['ownershipid'] . " " .$totalownership['titleno'];
    }
}

The $totalownerships array size is 52225. Is there a better way of writing this code so that it doesn'e take long time to execute ?

Answer 1

This will be a lot faster, using PHP's speedy built-in array manipulation tools to eliminate array searches in a loop:

// Add all titles to $totaltitles, for added speed
foreach ($totalownerships as $totalownership) {
    $totaltitles[] = $totalownership['titleno'];
}

// For PHP 5.5+ you can use array_column() to get just the titleno field
//$totaltitles = array_column($totalownership, 'titleno');

// Use array_unique() to eliminate duplicate titles from $totaltitles
array_unique($totaltitles);

// Use count() to get a total count of $totaltitles
$result['totalowns'] = count($totaltitles);

// Use implode() for concatenation of title names
$result['ownershipid'] .= " " . implode(" ", $totaltitles);

For more PHP performance tips, check: PHP Bench