Question

我有非常复杂的laravel雄辩集合，需要按照projectid，date，username进行排序。

我一直在搜索谷歌，但没有人询问或写过这种复杂的类型。

如果我只使用带有sortBy函数的desc或asc命令。它可以工作，但如果我尝试使用desc / asc两者混合..

我该如何解决这个问题？

收集结构

collection {
    array (size=148)
      0 => 
          attribute:
                id:100,
                date:"2015-02-03"
          relations: 
               0 project(belongstomany relationship)
                      projectid: 1
               1 user(belongstomany relationship)
                      username:"test"
}

这应该像这样排序

project id(desc)   date(desc)  name(asc)
9                  2015-02-31  test1
9                  2015-02-30  test2
8                  2015-02-30  test2
7                  2015-02-29  test3
6                  2015-02-28  test4
5                  2015-02-27  test5

Answer 1

您可以执行所需操作，但必须使用sort()方法，而不是sortBy()方法。 sort()方法将采用闭包，您可以使用它来定义自定义排序算法。基本上，如果你将一个闭包传递给sort()，它会用你的闭包调用PHP的usort()来对项目进行排序。

这只是您正在寻找的内容的粗略概念。你可能不得不调整它，因为你发布的内容很少有不确定性。您可以将其定义为传递到sort()的实际函数，或者您可以将其作为匿名函数传递给sort()。

function ($a, $b) {
    /**
     * Your question states that project is a belongsToMany relationship.
     * This means that project is a Collection that may contain many project
     * objects, and you need to figure out how you want to handle that. In
     * this case, I just take the max projectid from the Collection (max,
     * since this field will be sorted desc).
     * 
     * If this is really just a belongsTo, you can simplify this down to
     * just $a->project->projectid, etc.
     */
    $aFirst = $a->project->max('projectid');
    $bFirst = $b->project->max('projectid');

    /**
     * If the projectids are equal, we have to dig down to our next comparison.
     */    
    if ($aFirst == $bFirst) {
        /**
         * Since the first sort field (projectids) is equal, we have to check
         * the second sort field.
         */

        /**
         * If the dates are equal, we have to dig down to our next comparison.
         */
        if ($a->date == $b->date) {
            /**
             * Your question states that user is a belongsToMany relationship.
             * This means that user is a Collection that may contain many user
             * objects, and you need to figure out how you want to handle that.
             * In this case, I just take the min username from the Collection
             * (min, since this field will be sorted asc).
             */
            $aThird = $a->user->min('username');
            $bThird = $b->user->min('username');

            /**
             * If the final sort criteria is equal, return 0 to tell usort
             * that these two array items are equal (for sorting purposes).
             */
            if ($aThird == $bThird) {
                return 0;
            }

            /**
             * To sort in ascending order, return -1 when the first item
             * is less than the second item.
             */
            return ($aThird < $bThird) ? -1 : 1;
        }

        /**
         * To sort in descending order, return +1 when the first item is
         * less than the second item.
         */
        return ($a->date < $b->date) ? 1 : -1;
    }

    /**
     * To sort in descending order, return +1 when the first item is
     * less than the second item.
     */
    return ($aFirst < $bFirst) ? 1 : -1;
}

有关usort()如何运作的详情，您可以check the docs。

php complex laravel eloquent collection sort

1 个答案: