Filters are used to do some changes in the data. It can be used by adding pipe character.

These are the types of filters in angular:

• uppercase: It converts any text to upper case.
• lowercase: It converts any text to lower case.
• currency: It converts into currency format.
• filter: It can filter array based on any given criteria.
• orderby: It can order array based on any given criteria.

uppercase filter:
You can use uppercase filter by adding it to an expression using pipe(|) character. Below is the code that shows employee full name in uppercase.

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

lowercase filter:
You can use lowercase filter by adding it to an expression using pipe(|) character. Below is the code that shows employee full name in lowercase.

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

currency filter:
currency filter can be used by adding it to an expression using pipe character. It will return a number.

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

filter filter:
It is used to filter by a particular name. In the below code subject name is used as filter to display only required subjects.
 

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 filter:
It is used to arrange data in some order. Below is the code that arrange subjects by order of marks.
 

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

You can check the demo here.