Laravel 嵌套的 foreach 返回重复项

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【中文标题】Laravel 嵌套的 foreach 返回重复项【英文标题】：Laravel nested foreach returns duplicates 【发布时间】：2020-09-23 11:50:05 【问题描述】：

我正在尝试显示所有用户拥有的课程。 课程详细信息显示正常，但是当我尝试使用第二个 foreach 循环获取用户进度时，它为所有课程返回相同的值。 注意：我无法从第一个 foreach 中获取进度，因为进度存储在 user_courses 表中，而其他课程详细信息（例如课程名称和描述）存储在 course 表中。 代码如下：

         @foreach($user->courses as $course) 
                <div class="course-flex-item">  
                    <div class="course-header">
                        <strong>  $course['title']  </strong>
                    </div>
                    <div class="course-description">
                         $course['description']  
                    </div>
                    <div class="continue-button">
                        <button>Continue</button>
                    </div>
                    <div class="image-container">
                        <img class="course-image" src="https://www.w3.org/html/logo/downloads/HTML5_Badge_256.png" >
                        @foreach($user->user_courses as $user_course)                
                            <div class="progress">
                                <div class="progress-bar"  role="progressbar" aria-valuenow="70"
                                aria-valuemin="0" aria-valuemax="100" style="width:  $user_course['progress'] %;background-color: #f64c71;font-family:'Montserrat';font-weight:bold">
                                    <span class=""> $user_course['progress'] %</span>
                                </div>
                            </div>
                        @endforeach

                    </div>
                </div>
        @endforeach

例如，如果用户有 2 门课程，其中一门完成率为 12%，另一门完成率为 30%，则这两门课程都显示为 30%。

var_dump($user_courses): 第一道菜：

bject(App\User_Course)#1242 (27)  ["guarded":protected]=> array(0)   ["connection":protected]=> string(5) "mysql" ["table":protected]=> string(13) "user__courses" ["primaryKey":protected]=> string(2) "id" ["keyType":protected]=> string(3) "int" ["incrementing"]=> bool(true) ["with":protected]=> array(0)   ["withCount":protected]=> array(0)   ["perPage":protected]=> int(15) ["exists"]=> bool(true) ["wasRecentlyCreated"]=> bool(false) ["attributes":protected]=> array(6)  ["id"]=> int(6) ["user_id"]=> int(2) ["course_id"]=> int(2) ["progress"]=> string(2) "20" ["created_at"]=> NULL ["updated_at"]=> NULL  ["original":protected]=> array(6)  ["id"]=> int(6) ["user_id"]=> int(2) ["course_id"]=> int(2) ["progress"]=> string(2) "20" ["created_at"]=> NULL ["updated_at"]=> NULL  ["changes":protected]=> array(0)   ["casts":protected]=> array(0)   ["classCastCache":protected]=> array(0)   ["dates":protected]=> array(0)   ["dateFormat":protected]=> NULL ["appends":protected]=> array(0)   ["dispatchesEvents":protected]=> array(0)   ["observables":protected]=> array(0)   ["relations":protected]=> array(0)   ["touches":protected]=> array(0)   ["timestamps"]=> bool(true) ["hidden":protected]=> array(0)   ["visible":protected]=> array(0)   ["fillable":protected]=> array(0)    
12%
object(App\User_Course)#1245 (27)  ["guarded":protected]=> array(0)   ["connection":protected]=> string(5) "mysql" ["table":protected]=> string(13) "user__courses" ["primaryKey":protected]=> string(2) "id" ["keyType":protected]=> string(3) "int" ["incrementing"]=> bool(true) ["with":protected]=> array(0)   ["withCount":protected]=> array(0)   ["perPage":protected]=> int(15) ["exists"]=> bool(true) ["wasRecentlyCreated"]=> bool(false) ["attributes":protected]=> array(6)  ["id"]=> int(8) ["user_id"]=> int(2) ["course_id"]=> int(3) ["progress"]=> string(2) "12" ["created_at"]=> NULL ["updated_at"]=> NULL  ["original":protected]=> array(6)  ["id"]=> int(8) ["user_id"]=> int(2) ["course_id"]=> int(3) ["progress"]=> string(2) "12" ["created_at"]=> NULL ["updated_at"]=> NULL  ["changes":protected]=> array(0)   ["casts":protected]=> array(0)   ["classCastCache":protected]=> array(0)   ["dates":protected]=> array(0)   ["dateFormat":protected]=> NULL ["appends":protected]=> array(0)   ["dispatchesEvents":protected]=> array(0)   ["observables":protected]=> array(0)   ["relations":protected]=> array(0)   ["touches":protected]=> array(0)   ["timestamps"]=> bool(true) ["hidden":protected]=> array(0)   ["visible":protected]=> array(0)   ["fillable":protected]=> array(0)

第二门课程：

bject(App\User_Course)#1242 (27)  ["guarded":protected]=> array(0)   ["connection":protected]=> string(5) "mysql" ["table":protected]=> string(13) "user__courses" ["primaryKey":protected]=> string(2) "id" ["keyType":protected]=> string(3) "int" ["incrementing"]=> bool(true) ["with":protected]=> array(0)   ["withCount":protected]=> array(0)   ["perPage":protected]=> int(15) ["exists"]=> bool(true) ["wasRecentlyCreated"]=> bool(false) ["attributes":protected]=> array(6)  ["id"]=> int(6) ["user_id"]=> int(2) ["course_id"]=> int(2) ["progress"]=> string(2) "20" ["created_at"]=> NULL ["updated_at"]=> NULL  ["original":protected]=> array(6)  ["id"]=> int(6) ["user_id"]=> int(2) ["course_id"]=> int(2) ["progress"]=> string(2) "20" ["created_at"]=> NULL ["updated_at"]=> NULL  ["changes":protected]=> array(0)   ["casts":protected]=> array(0)   ["classCastCache":protected]=> array(0)   ["dates":protected]=> array(0)   ["dateFormat":protected]=> NULL ["appends":protected]=> array(0)   ["dispatchesEvents":protected]=> array(0)   ["observables":protected]=> array(0)   ["relations":protected]=> array(0)   ["touches":protected]=> array(0)   ["timestamps"]=> bool(true) ["hidden":protected]=> array(0)   ["visible":protected]=> array(0)   ["fillable":protected]=> array(0)    
12%
object(App\User_Course)#1245 (27)  ["guarded":protected]=> array(0)   ["connection":protected]=> string(5) "mysql" ["table":protected]=> string(13) "user__courses" ["primaryKey":protected]=> string(2) "id" ["keyType":protected]=> string(3) "int" ["incrementing"]=> bool(true) ["with":protected]=> array(0)   ["withCount":protected]=> array(0)   ["perPage":protected]=> int(15) ["exists"]=> bool(true) ["wasRecentlyCreated"]=> bool(false) ["attributes":protected]=> array(6)  ["id"]=> int(8) ["user_id"]=> int(2) ["course_id"]=> int(3) ["progress"]=> string(2) "12" ["created_at"]=> NULL ["updated_at"]=> NULL  ["original":protected]=> array(6)  ["id"]=> int(8) ["user_id"]=> int(2) ["course_id"]=> int(3) ["progress"]=> string(2) "12" ["created_at"]=> NULL ["updated_at"]=> NULL  ["changes":protected]=> array(0)   ["casts":protected]=> array(0)   ["classCastCache":protected]=> array(0)   ["dates":protected]=> array(0)   ["dateFormat":protected]=> NULL ["appends":protected]=> array(0)   ["dispatchesEvents":protected]=> array(0)   ["observables":protected]=> array(0)   ["relations":protected]=> array(0)   ["touches":protected]=> array(0)   ["timestamps"]=> bool(true) ["hidden":protected]=> array(0)   ["visible":protected]=> array(0)   ["fillable":protected]=> array(0)

【问题讨论】：

【参考方案1】： 
    @foreach($user->courses as $course) 
    <div class="course-flex-item">  
      <div class="course-header">
      <strong>  $course['title']  </strong>
      </div>
      <div class="course-description">
         $course['description']  
      </div>
      <div class="continue-button">
        <button>Continue</button>
      </div>
      <div class="image-container">
      <img class="course-image" src="https://www.w3.org/html/logo/downloads/HTML5_Badge_256.png" >
                          @if(is_array($course)
                            @foreach($course as $user_course)                
                                <div class="progress">
                                    <div class="progress-bar"  role="progressbar" aria-valuenow="70"
                                    aria-valuemin="0" aria-valuemax="100" style="width:  $user_course['progress'] %;background-color: #f64c71;font-family:'Montserrat';font-weight:bold">
                                        <span class=""> $user_course['progress'] %</span>
                                    </div>
                                </div>
                            @endforeach
                         @endif
                        </div>
                    </div>
            @endforeach

【讨论】：

Ljaz，这甚至没有打印进度 App\User_Course #1242 ▼ #guarded: [] #connection: "mysql" #table: "user__courses" #primaryKey: "id" #keyType: "int" +incrementing: true #with : [] #withCount: [] #perPage: 15 +exists: true +wasRecentlyCreated: false #attributes: array:6 [▶] #original: array:6 [▶] #changes: [] #casts: [] #classCastCache : [] #dates: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true #hidden: [] #visible: [ ] #fillable: [] Ljaz 这是它打印的内容 请使用 var dump 或 print_r 它没有显示所有记录 添加了@Naeem Ljaz【参考方案2】：

消除第二个 foreach。然后像这样获得进度

 $course->user_course->where('user_id', $user->id)->first() != null ?  $course->user_course->where('user_id', $user->id)->first()->progress  : 0

【讨论】：

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