给定这个数组:

$inventory = array(

   array("type"=>"fruit", "price"=>3.50),
   array("type"=>"milk", "price"=>2.90),
   array("type"=>"pork", "price"=>5.43),

);

我想按价格排序$inventory的元素,以获得:

$inventory = array(

   array("type"=>"pork", "price"=>5.43),
   array("type"=>"fruit", "price"=>3.50),
   array("type"=>"milk", "price"=>2.90),

);

我该怎么做呢?


当前回答

你可以将usort与匿名函数一起使用,例如:

usort($inventory, function ($a, $b) { return strnatcmp($a['price'], $b['price']); });

其他回答

$inventory = 
    array(array("type"=>"fruit", "price"=>3.50),
          array("type"=>"milk", "price"=>2.90),
          array("type"=>"pork", "price"=>5.43),
          );

function pricesort($a, $b) {
  $a = $a['price'];
  $b = $b['price'];
  if ($a == $b)
    return 0;
  return ($a > $b) ? -1 : 1;
}

usort($inventory, "pricesort");
// uksort($inventory, "pricesort");

print("first: ".$inventory[0]['type']."\n\n");
// for usort(): prints milk (item with lowest price)
// for uksort(): prints fruit (item with key 0 in the original $inventory)

// foreach prints the same for usort and uksort.
foreach($inventory as $i){
  print($i['type'].": ".$i['price']."\n");
}

输出:

first: pork

pork: 5.43
fruit: 3.5
milk: 2.9

这个函数在所有主要的PHP版本上都可以100%运行,并且在PHP5, PHP7, PHP8上都进行了测试。

    function sort_my_array($array, $order_by, $order)
    {
        switch ($order) {
            case "asc":
                usort($array, function ($first, $second) use ($order_by) {
                    if (version_compare(PHP_VERSION, '7.0.0') >= 0) {
                        return $first[$order_by] <=> $second[$order_by];
                    } else {
                        $array_cmp = strcmp($first[$order_by], $second[$order_by]);
                        return $array_cmp ;
                    }
                });
                break;
            case "desc":
                usort($certificates, function ($first, $second) use ($order_by) {
                    if (version_compare(PHP_VERSION, '7.0.0') >= 0) {
                        return $first[$order_by] <=> $second[$order_by];
                    } else {
                        $array_cmp = strcmp($first[$order_by], $second[$order_by]);
                        return -$array_cmp ;
                    }
                });
                break;
            default:
                break;
        }
        return $array;
    }

这是我很久以前发现的一个方法,并进行了一些清理。这工作得很好,并且可以快速更改为接受对象。

/**
 * A method for sorting arrays by a certain key:value.
 * SortByKey is the key you wish to sort by
 * Direction can be ASC or DESC.
 *
 * @param $array
 * @param $sortByKey
 * @param $sortDirection
 * @return array
 */
private function sortArray($array, $sortByKey, $sortDirection) {

    $sortArray = array();
    $tempArray = array();

    foreach ( $array as $key => $value ) {
        $tempArray[] = strtolower( $value[ $sortByKey ] );
    }

    if($sortDirection=='ASC'){ asort($tempArray ); }
        else{ arsort($tempArray ); }

    foreach ( $tempArray as $key => $temp ){
        $sortArray[] = $array[ $key ];
    }

    return $sortArray;

}

要更改排序对象的方法,只需更改以下行:

$tempArray[] = strtolower($value[$sortByKey]); 来 $tempArray[] = strtolower($value->$sortByKey);

要运行该方法,只需执行

盘存、’price’’ASC’sortArray(美元);

完整的动态功能 我跳到这里进行关联数组排序,并在http://php.net/manual/en/function.sort.php上找到了这个惊人的函数。这个函数是非常动态的,用指定的键按升序和降序排序。

按特定键对数组排序的简单函数。维护索引关联

<?php

function array_sort($array, $on, $order=SORT_ASC)
{
    $new_array = array();
    $sortable_array = array();

    if (count($array) > 0) {
        foreach ($array as $k => $v) {
            if (is_array($v)) {
                foreach ($v as $k2 => $v2) {
                    if ($k2 == $on) {
                        $sortable_array[$k] = $v2;
                    }
                }
            } else {
                $sortable_array[$k] = $v;
            }
        }

        switch ($order) {
            case SORT_ASC:
                asort($sortable_array);
            break;
            case SORT_DESC:
                arsort($sortable_array);
            break;
        }

        foreach ($sortable_array as $k => $v) {
            $new_array[$k] = $array[$k];
        }
    }

    return $new_array;
}

$people = array(
    12345 => array(
        'id' => 12345,
        'first_name' => 'Joe',
        'surname' => 'Bloggs',
        'age' => 23,
        'sex' => 'm'
    ),
    12346 => array(
        'id' => 12346,
        'first_name' => 'Adam',
        'surname' => 'Smith',
        'age' => 18,
        'sex' => 'm'
    ),
    12347 => array(
        'id' => 12347,
        'first_name' => 'Amy',
        'surname' => 'Jones',
        'age' => 21,
        'sex' => 'f'
    )
);

print_r(array_sort($people, 'age', SORT_DESC)); // Sort by oldest first
print_r(array_sort($people, 'surname', SORT_ASC)); // Sort by surname

这个函数是可重用的:

function usortarr(&$array, $key, $callback = 'strnatcasecmp') {
    uasort($array, function($a, $b) use($key, $callback) {
        return call_user_func($callback, $a[$key], $b[$key]);
    });
}

默认情况下,它在字符串值上工作得很好,但如果所有值都是数字,则必须为数字比较函数指定子回调函数。