如何使用ng-repeat删除冗余代码

debugcn 发表于 Dev

泡菜人

我正在学习网络编程和AngularJS。HTML文件中有很多冗余代码，但是我不知道如何删除它们。

HTML档案：

<select id="selectSearch" ng-model="searchValue">
    <option value="7">7</option>
    <option value="6">6</option>
    <option value="5">5</option>
    <option value="4">4</option>
    <option value="3">3</option>
    <option value="2">2</option>
    <option value="1">1</option>
</select>
...
<tr>
    <td></td>
    <td colspan="3">Class</td>
    <td x-ng-if="searchValue >= 1">{{ getClass(studentYear)   }}</td>
    <td x-ng-if="searchValue >= 2">{{ getClass(studentYear+1) }}</td>
    <td x-ng-if="searchValue >= 3">{{ getClass(studentYear+2) }}</td>
    <td x-ng-if="searchValue >= 4">{{ getClass(studentYear+3) }}</td>
    <td x-ng-if="searchValue >= 5">{{ getClass(studentYear+4) }}</td>
    <td x-ng-if="searchValue >= 6">{{ getClass(studentYear+5) }}</td>
    <td x-ng-if="searchValue >= 7">{{ getClass(studentYear+6) }}</td>
</tr>
<tr>
    <td></td>
    <td colspan="3">Grades</td>
    <td x-ng-if="searchValue >= 1">{{ getGrades(studentYear)   }}</td>
    <td x-ng-if="searchValue >= 2">{{ getGrades(studentYear+1) }}</td>
    <td x-ng-if="searchValue >= 3">{{ getGrades(studentYear+2) }}</td>
    <td x-ng-if="searchValue >= 4">{{ getGrades(studentYear+3) }}</td>
    <td x-ng-if="searchValue >= 5">{{ getGrades(studentYear+4) }}</td>
    <td x-ng-if="searchValue >= 6">{{ getGrades(studentYear+5) }}</td>
    <td x-ng-if="searchValue >= 7">{{ getGrades(studentYear+6) }}</td>
</tr>
<tr>
    <td></td>
    <td colspan="3">Status</td>
    <td x-ng-if="searchValue >= 1">{{ getStatus(studentYear)   }}</td>
    <td x-ng-if="searchValue >= 2">{{ getStatus(studentYear+1) }}</td>
    <td x-ng-if="searchValue >= 3">{{ getStatus(studentYear+2) }}</td>
    <td x-ng-if="searchValue >= 4">{{ getStatus(studentYear+3) }}</td>
    <td x-ng-if="searchValue >= 5">{{ getStatus(studentYear+4) }}</td>
    <td x-ng-if="searchValue >= 6">{{ getStatus(studentYear+5) }}</td>
    <td x-ng-if="searchValue >= 7">{{ getStatus(studentYear+6) }}</td>
</tr>
...

我想我需要使用ng-repeat && ng-init，但是在这种情况下我不知道如何使用它们。

亨里克·皮纳尔（Henrik Peinar）

由于实际上很难理解表背后的逻辑是什么，我举了一个相当笼统的示例，说明如何使用ng-repeat和ng-select来处理某些数据。

请参见下面的代码：

<div data-ng-controller="nodeTodayCtrl">
    <label for="selectYear">Select year you want info for</label>
    <select data-ng-model="selectedYear" data-ng-options="year for year in possibleYears"></select>

    <!-- we are assuming that there are in total of 9 classes and after that they've finished school -->
    <table>
        <tr>
            <td>Name</td>
            <td>Gender</td>
            <td>Is in class on selected year</td>
        </tr>
        <tr data-ng-repeat="student in students">
            <td>{{student.name}}</td>
            <td>{{student.gender}}</td>
            <td>{{ getClass(student, selectedYear); }}</td>
        </tr>
    </table>
</div>

Javascript：

$scope.possibleYears = [];
$scope.yearRange = 10;

// populate possible years, start from 0 to include current year
for(var i = 0; i <= $scope.yearRange;i++) {
    $scope.possibleYears.push((new Date()).getFullYear() + i);
}

$scope.getClass = function(student, selectedYear) {
    var currentYear = (new Date()).getFullYear();

    // default to current year
    if(!selectedYear) {
        selectedYear = currentYear;
    }
    var classIn = student.class + (selectedYear - currentYear);

    return (classIn > 9) ? 'Finished school '+ (classIn - 9) +' year(s) ago' : classIn;    
};

// your students data
$scope.students = [{}, ...];

请参阅小提琴以获得完整代码的工作示例：

http://jsfiddle.net/hpeinar/zwnbet95/

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