PHP – 更改字符排序顺序,例如“a”>“{”=真

我正在尝试自定义 PHP的usort函数来更改字符排序顺序.

目前,只有“*”符号字符等于具有小于字母字符的值,例如“a”,即“*”< “a”= TRUE.其他符号,例如“{”,具有大于字母的值,即“{”< “a”=假. 我想排序所以值“{*}”位于排序数组的顶部,就像值是“*”一样.这是我目前正在使用的函数,用于按对象的多个属性对对象数组进行排序. [归因：它是usort docs上Will Shaver’s代码的修改版本.]

function osort($array,$properties) {
    //Cast to an array and specify ascending order for the sort if the properties aren't already
    if (!is_array($properties)) $properties = [$properties => true];

    //Run the usort,using an anonymous function / closures
    usort($array,function($a,$b) use ($properties) {
        //Loop through each specified object property to sort by
        foreach ($properties as $property => $ascending) {
            //If they are the same,continue to the next property
            if ($a -> $property != $b -> $property) {
                //Ascending order search for match
                if ($ascending) {
                    //if a's property is greater than b,return 1,otherwise -1
                    return $a -> $property > $b -> $property ? 1 : -1;
                }
                //Descending order search for match
                else {
                    //if b's property is greater than a's,otherwise -1
                    return $b -> $property > $a -> $property ? 1 : -1;
                }
            }
        }
        //Default return value (no match found)
        return -1;
    });

    //Return the sorted array
    return $array;
}

解决方法

如果按照您定义的顺序对某些字符进行优先级排序,然后使用常规strcmp呢？

像这样的东西：

<?PHP

$list = [ 'abc','{a}','*','{*}','{abc','}a',]; // An array of strings to sort

$customOrderPrioritized = ['{','}']; // Add any characters here to prioritize them,in the order they appear in this array

function ustrcmp($a,$b,$customOrderPrioritized) {
    if ($a === $b) return -1; // same,doesn't matter who goes first

    $n = min(strlen($a),strlen($b)); // compare up to the length of the shortest string
    for ($i = 0; $i < $n; $i++) {
        if ($a[$i] === $b[$i]) continue; // matching character,continue to compare next

        $a_prio = in_array($a[$i],$customOrderPrioritized);
        $b_prio = in_array($b[$i],$customOrderPrioritized);

        // If either one has a prioritized char...
        if ($a_prio || $b_prio) {
            if ($a_prio && $b_prio) {
                // Both are prioritized,check which one is first...
                return array_search($a[$i],$customOrderPrioritized) <= array_search($b[$i],$customOrderPrioritized) ? -1 : 1;
            } elseif ($a_prio) {
                return -1; // a < b
            } else { // must be $b_prio
                return +1; // b > a
            }
        }
        return strcmp($a[i],$b[$i]); // compare single character
    }
    // if they have identical beginning,shortest should be first
    return strlen($a) <= strlen($b) ? -1 : +1;
}

usort(
    $list,$b) use ($customOrderPrioritized){
        return ustrcmp($a,$customOrderPrioritized);        
    }
); // run custom comparison function,pass in $customOrderPrioritized (or make it global)

print_r($list); // print the list

/* The sorted array should look like:
Array
(
    [0] => {*}
    [1] => {a}
    [2] => {abc
    [3] => *
    [4] => }a
    [5] => abc
)
*/