我有一个球员列表，每个球员都属于一个团体。如何使用过滤器列出每个团体的用户？
[{name: 'Gene', team: 'team alpha'},
{name: 'George', team: 'team beta'},
{name: 'Steve', team: 'team gamma'},
{name: 'Paula', team: 'team beta'},
{name: 'Scruath of the 5th sector', team: 'team gamma'}];
我正在寻找这个结果:
JS:
$scope.players = [
{name: 'Gene', team: 'alpha'},
{name: 'George', team: 'beta'},
{name: 'Steve', team: 'gamma'},
{name: 'Paula', team: 'beta'},
{name: 'Scruath', team: 'gamma'}
];
HTML：
<ul ng-repeat="(key, value) in players | groupBy: 'team'">
Group name: {{ key }}
<li ng-repeat="player in value">
player: {{ player.name }}
</li>
</ul>
结果:
组名: alpha
* 玩家: Gene
组名: beta
* 玩家: George
* 玩家: Paula
组名: gamma
* 玩家: Steve
* 玩家: Scruath
更新: jsbin 记住使用angular.filter的基本要求，特别是注意您必须将其添加到模块的依赖项中：
(1) 您可以使用4种不同的方法安装angular-filter：
- 克隆并构建此存储库
- 通过Bower：在终端上运行$ bower install angular-filter
- 通过npm：在终端上运行$ npm install angular-filter
- 通过cdnjs http://www.cdnjs.com/libraries/angular-filter
(2) 在index.html中包含angular-filter.js（或angular-filter.min.js），在包含Angular本身之后。
(3) 将'angular.filter'添加到您的主模块的依赖列表中。
除了上面接受的答案，我使用 underscore.js 库创建了一个通用的 'groupBy' 过滤器。
JSFiddle（已更新）：http://jsfiddle.net/TD7t3/
该过滤器：
app.filter('groupBy', function() {
return _.memoize(function(items, field) {
return _.groupBy(items, field);
}
);
});
注意'memoize'函数的调用。这个underscore方法缓存了函数的结果，防止Angular在每次评估筛选器表达式时都重新计算结果，从而防止Angular达到digest迭代限制。
HTML
<ul>
<li ng-repeat="(team, players) in teamPlayers | groupBy:'team'">
{{team}}
<ul>
<li ng-repeat="player in players">
{{player.name}}
</li>
</ul>
</li>
</ul>
app.filter('groupBy', function($parse) {
return _.memoize(function(items, field) {
var getter = $parse(field);
return _.groupBy(items, function(item) {
return getter(item);
});
});
});
控制器（带有嵌套对象）
app.controller('homeCtrl', function($scope) {
var teamAlpha = {name: 'team alpha'};
var teamBeta = {name: 'team beta'};
var teamGamma = {name: 'team gamma'};
$scope.teamPlayers = [{name: 'Gene', team: teamAlpha},
{name: 'George', team: teamBeta},
{name: 'Steve', team: teamGamma},
{name: 'Paula', team: teamBeta},
{name: 'Scruath of the 5th sector', team: teamGamma}];
});
使用sortBy表达式的HTML代码
<li ng-repeat="(team, players) in teamPlayers | groupBy:'team.name'">
{{team}}
<ul>
<li ng-repeat="player in players">
{{player.name}}
</li>
</ul>
</li>
JSFiddle：http://jsfiddle.net/k7fgB/2/
_.memoize( ... , function (items, field) { return _.pluck(items,'name').toString() + '-' + field})。这个 SO 答案有更多细节：https://dev59.com/2mQn5IYBdhLWcg3w36TV#16513030 - Chad von Nau首先使用一个过滤器进行循环，该过滤器将仅返回唯一的团队，然后使用嵌套循环返回当前团队的所有球员：
http://jsfiddle.net/plantface/L6cQN/
HTML：
<div ng-app ng-controller="Main">
<div ng-repeat="playerPerTeam in playersToFilter() | filter:filterTeams">
<b>{{playerPerTeam.team}}</b>
<li ng-repeat="player in players | filter:{team: playerPerTeam.team}">{{player.name}}</li>
</div>
</div>
脚本：
function Main($scope) {
$scope.players = [{name: 'Gene', team: 'team alpha'},
{name: 'George', team: 'team beta'},
{name: 'Steve', team: 'team gamma'},
{name: 'Paula', team: 'team beta'},
{name: 'Scruath of the 5th sector', team: 'team gamma'}];
var indexedTeams = [];
// this will reset the list of indexed teams each time the list is rendered again
$scope.playersToFilter = function() {
indexedTeams = [];
return $scope.players;
}
$scope.filterTeams = function(player) {
var teamIsNew = indexedTeams.indexOf(player.team) == -1;
if (teamIsNew) {
indexedTeams.push(player.team);
}
return teamIsNew;
}
}
我最初采用了Plantface的答案，但我不喜欢在我的视图中看到的语法。
我修改了它，使用$q.defer来后处理数据并返回唯一团队列表，然后将其用作过滤器。
http://plnkr.co/edit/waWv1donzEMdsNMlMHBa?p=preview
<ul>
<li ng-repeat="team in teams">{{team}}
<ul>
<li ng-repeat="player in players | filter: {team: team}">{{player.name}}</li>
</ul>
</li>
</ul>
app.controller('MainCtrl', function($scope, $q) {
$scope.players = []; // omitted from SO for brevity
// create a deferred object to be resolved later
var teamsDeferred = $q.defer();
// return a promise. The promise says, "I promise that I'll give you your
// data as soon as I have it (which is when I am resolved)".
$scope.teams = teamsDeferred.promise;
// create a list of unique teams. unique() definition omitted from SO for brevity
var uniqueTeams = unique($scope.players, 'team');
// resolve the deferred object with the unique teams
// this will trigger an update on the view
teamsDeferred.resolve(uniqueTeams);
});
两个答案都很好，所以我将它们移动到一个指令中，使其可以重复使用，而不必定义第二个作用域变量。
这里是示例，如果你想看它的实现
下面是指令：
var uniqueItems = function (data, key) {
var result = [];
for (var i = 0; i < data.length; i++) {
var value = data[i][key];
if (result.indexOf(value) == -1) {
result.push(value);
}
}
return result;
};
myApp.filter('groupBy',
function () {
return function (collection, key) {
if (collection === null) return;
return uniqueItems(collection, key);
};
});
那么它可以按如下方式使用：
<div ng-repeat="team in players|groupBy:'team'">
<b>{{team}}</b>
<li ng-repeat="player in players | filter: {team: team}">{{player.name}}</li>
</div>
我最初写下了这个答案，是因为Ariel M.建议的旧版本解决方案与其他$filters结合使用会触发一个"无限$digest循环错误"(infdig)。幸运的是，在最新版本的angular.filter中已经解决了这个问题。
我建议采用以下实现方式，没有这个问题：
angular.module("sbrpr.filters", [])
.filter('groupBy', function () {
var results={};
return function (data, key) {
if (!(data && key)) return;
var result;
if(!this.$id){
result={};
}else{
var scopeId = this.$id;
if(!results[scopeId]){
results[scopeId]={};
this.$on("$destroy", function() {
delete results[scopeId];
});
}
result = results[scopeId];
}
for(var groupKey in result)
result[groupKey].splice(0,result[groupKey].length);
for (var i=0; i<data.length; i++) {
if (!result[data[i][key]])
result[data[i][key]]=[];
result[data[i][key]].push(data[i]);
}
var keys = Object.keys(result);
for(var k=0; k<keys.length; k++){
if(result[keys[k]].length===0)
delete result[keys[k]];
}
return result;
};
});
$filter所采取的步骤、遇到的问题以及从中学到的东西的文章。angular-filter版本-0.5.0，不再有异常了。
groupBy可以与任何过滤器链接。
此外，您的测试用例非常出色，已成功完成-这是一个plunker。
谢谢。 - a8m除了已接受的答案外，如果您想按多列分组，也可以使用此方法：
<ul ng-repeat="(key, value) in players | groupBy: '[team,name]'">
function controller($scope, $http, groupByFilter) {
var groupedData = groupByFilter(originalArray, 'groupPropName');
}
https://github.com/a8m/angular-filter/wiki/Common-Questions#inject-filters
angular.filter模块。 - PucegroupBy: 'team || age'。这里有一些fiddle来演示它。谢谢。 - a8m