$filter
1、 currency格式化数字为货币格式。
var orderBy = $filter('orderBy');
$scope.list =orderBy(list,'age',true);
var price ="11.11";
var currency = $filter('currency');
console.log(currency);
$scope.price =currency(price,'$');
2、lowercase格式化字符串为小写。
3、uppercase格式化字符串为大写。
var hello ='Hello World!!!!!';
var uppercase = $filter('uppercase');
$scope.hello =uppercase(hello);
var lowercase = $filter('lowercase');
$scope.low =lowercase(hello);
4、orderBy根据某个表达式排列数组
var list = [
{name:'css',age:6},
{name:'jss',age:26},
{name:'html',age:16},
{name:'json',age:166},
];
5、number angularjs过滤器number，用来精确浮点数
var number = $filter('number');
var count =number(123.456789,2);//123.46
var count =number(123.12345,10);//123.1234500000
6、limitTo (限制数组长度或字符串长度)
var limitTo = $filter('limitTo');
console.log(limitTo('123456789',1)); //1
console.log(limitTo('123456789',2)); //12
console.log(limitTo('123456789',1,3)); //4
4、filter从数组项中选择一个子集 还没学习，暂时用不着
