AngularJS 过滤器

过滤器用于修改数据。它们可以在表达式或指令中使用管道符（|）进行组合。下面的列表显示了常用的过滤器。

序号	名称及描述
1	uppercase 将文本转换为大写文本。
2	lowercase 将文本转换为小写文本。
3	currency 将文本格式化为货币格式。
4	filter 根据提供的条件将数组筛选为子集。
5	orderby 根据提供的条件对数组进行排序。

大写过滤器

使用管道字符将大写过滤器添加到表达式中。在这里，我们已将大写过滤器添加到打印学生姓名的表达式中，使其以全大写字母显示。

Enter first name:<input type = "text" ng-model = "student.firstName">
Enter last name: <input type = "text" ng-model = "student.lastName">
Name in Upper Case: {{student.fullName() | uppercase}}

小写过滤器

使用管道符号将小写过滤器添加到表达式中。在这里，我们添加了小写过滤器来打印学生姓名的全部小写字母。

Enter first name:<input type = "text" ng-model = "student.firstName">
Enter last name: <input type = "text" ng-model = "student.lastName">
Name in Lower Case: {{student.fullName() | lowercase}}

货币过滤器

使用竖线字符，为返回数字的表达式添加货币过滤器。在这里，我们通过货币格式化添加了货币过滤器来打印费用。

Enter fees: <input type = "text" ng-model = "student.fees">
fees: {{student.fees | currency}}

筛选

为了只显示所需的科目，我们使用subjectName作为筛选器。

Enter subject: <input type = "text" ng-model = "subjectName">
Subject:
<ul>
   <li ng-repeat = "subject in student.subjects | filter: subjectName">
      {{ subject.name + ', marks:' + subject.marks }}
   </li>
</ul>

OrderBy筛选器

要按照分数对科目进行排序，我们使用orderBy marks。

Subject:
<ul>
   <li ng-repeat = "subject in student.subjects | orderBy:'marks'">
      {{ subject.name + ', marks:' + subject.marks }}
   </li>
</ul>

示例

以下示例展示了使用上述所有过滤器的方式。

testAngularJS.htm

<html>
   <head>
      <title>Angular JS Filters</title>
      <script src = "https://ajax.googleapis.com/ajax/libs/angularjs/1.3.14/angular.min.js">
      </script>
   </head>

   <body>
      <h2>AngularJS Sample Application</h2>

      <div ng-app = "mainApp" ng-controller = "studentController">
         <table border = "0">
            <tr>
               <td>Enter first name:</td>
               <td><input type = "text" ng-model = "student.firstName"></td>
            </tr>
            <tr>
               <td>Enter last name: </td>
               <td><input type = "text" ng-model = "student.lastName"></td>
            </tr>
            <tr>
               <td>Enter fees: </td>
               <td><input type = "text" ng-model = "student.fees"></td>
            </tr>
            <tr>
               <td>Enter subject: </td>
               <td><input type = "text" ng-model = "subjectName"></td>
            </tr>
         </table>
         <br/>

         <table border = "0">
            <tr>
               <td>Name in Upper Case: </td><td>{{student.fullName() | uppercase}}</td>
            </tr>
            <tr>
               <td>Name in Lower Case: </td><td>{{student.fullName() | lowercase}}</td>
            </tr>
            <tr>
               <td>fees: </td><td>{{student.fees | currency}}
               </td>
            </tr>
            <tr>
               <td>Subject:</td>
               <td>
                  <ul>
                     <li ng-repeat = "subject in student.subjects | filter: subjectName |orderBy:'marks'">
                        {{ subject.name + ', marks:' + subject.marks }}
                     </li>
                  </ul>
               </td>
            </tr>
         </table>
      </div>

      <script>
         var mainApp = angular.module("mainApp", []);

         mainApp.controller('studentController', function( $scope) {$ scope.student = {
               firstName: "Mahesh",
               lastName: "Parashar",
               fees:500,

               subjects:[
                  {name:'Physics',marks:70},
                  {name:'Chemistry',marks:80},
                  {name:'Math',marks:65}
               ],
               fullName: function() {
                  var studentObject;
                  studentObject = $scope.student;
                  return studentObject.firstName + " " + studentObject.lastName;
               }
            };
         });
      </script>

   </body>
</html>