使用usort（）排序数组时是否可以设置两个起始值？

Question

$currency[0] = '$';
$currency[1] = 'WON';
$currency[2] = 'A$';
$currency[3] = '€';
$currency[4] = '¥';

I want to sort $currency using usort(). But I want $ to be first and then ¥ be the second and then the rest will be sorted alphabetically. Is it possible using usort() ?

Answer 1

In your case you may use sort with some array_* functions:

$prime = array('$', '¥');
$matches = array_intersect($currency, $prime);
$currency = array_diff($currency, $prime);
sort($currency);
$currency = array_merge($matches, $currency);

UPDATE:

Alternative solution using usort:

$prime = array('$', '¥');
usort($currency, function ($a, $b) use ($prime) {
    $i1 = array_search($a, $prime);
    $i2 = array_search($b, $prime);
    if ($i1 !== false || $i2 !== false)
        return $i2 === false || $i1 !== false && $i1 < $i2? -1 : 1;
    return $a < $b? -1 : ($a == $b? 0 : 1);
});