How to apply class to div dynamically using AngularJS - html

Question

I want to switch to div with class="col-md-x" depending upon the number of student object i am receiving.
E.x: Sample
if i am getting only one JSON object then i want to a div with class should be like(class="col-md-12").
if am getting two JSON object then i want to switch to a div with class="col-md-6".
<div class="container">
<div class="row">
<div class="col-md-12">
<div clss="row">
<div ng-repeat="c in vm.students" class="col-md-12">
<div calss="thimbnail">
<div class="Option div 1">
</div>
</div>
</div>
<div ng-repeat="c in vm.students" class="col-md-6">
<div calss="thimbnail col-md-">
<div class="Option div 2">
</div>
</div>
</div>
<div ng-repeat="c in vm.students" class="col-md-4">
<div calss="thimbnail col-md-">
<div class="Option div 3">
</div>
</div>
</div>
</div>
</div>
</div>
</div>

Answer 1

Use ng-class like below,
ng-class="{class}[condition]"
In your case ,
ng-class="{1:'col-md-12', 2:'col-sm-6'}[vm.students.length]"
For your reference, Detailed explanation

Answer 2

You have calss instead of class in the example code. I hope that is a typo.
To address to your problem you can make use of ng-class where you can assign classes based on conditions
More document on ng-class
Code Snippet:
<div class="container">
<div class="row">
<div class="col-md-12">
<div clss="row">
<div ng-repeat="c in vm.students" ng-class="{col-md-12:vm.students.length === 1,col-md-6:vm.students.length === 2">
<div calss="thimbnail">
<div class="Option div 1">
</div>
</div>
</div>
</div>
</div>
</div>
</div>