对于其中一个属性是不确定的NG-重复过滤器 [英] ng-repeat filter for where an attribute is undefined

问题描述

我希望这将是棱角分明非常简单。

我有翻译人员和其他用户的列表

  [{用户：'A'，语言：'法国'，'英语'，'西班牙']}，
{用户：'B'}]
 

然后我有一个NG重复，我只想显示谁拥有语言的用户。

  NG-重复=翻译用户|过滤器：{}语言
 

但不幸的是，我似乎无法弄清楚如何通过一个属性的存在进行筛选。
我已经试过所有方式

  {语言：'！未定义'}
{languages​​.length＆GT; 0}
{languages​​.length：0！'}
 

我不希望有写这个外部滤波器，因为我敢肯定，这是可能的角度，我只是没有能够得到正确的行话。

解决方案

 ＆LT; D​​IV NG重复=翻译用户|过滤器：{语言：'！ }＆GT;
 

说明：

考虑如下的列表：

  $ scope.items = [
    {
        propertyOne：'A'，
        propertyTwo：'你好'
    }，
    {
        propertyOne：'B'，
        propertyTwo：空
    }，
    {
        propertyOne：'C'，
        propertyTwo：未定义
    }，
    {
        propertyOne：'D'
    }
];
 

'！筛选出具有某种属性或具有某种属性，是不是未定义或为空对象的对象：

 ＆LT;在项目DIV NG-重复=项|过滤器：{propertyTwo：'!! }＆GT;
    {{item.propertyOne}}
＆LT; / DIV＆GT;
！＆LT;  - 输出：一个 - ＆GT;
 

！

过滤掉没有一定的财产或具有某种属性，该属性未定义或空对象的对象：

 ＆LT;在项目DIV NG-重复=项|过滤器：'！'：{propertyTwo }＆GT;
    {{item.propertyOne}}
＆LT; / DIV＆GT;
＆LT;  - 输出：B C D  - ＆GT;
 

Plnkr

请注意：它不会对性能与价值如0，虚假或空字符串工作（''）

。

编辑：previous答案是从plunkr例子不同。我固定他们通过交换'！和'！'。

I was hoping this would be really simple in angular.

I have an list with translators and other users

[{user: 'a',languages:['french','english','spanish']},
{user: 'b'}]

I then have an ng-repeat where I only want to display the users who have languages

ng-repeat="translator in users | filter: {languages}"

but unfortunately, I can't seem to figure out how to filter by the existence of an attribute. I've tried all manner of

{languages:'!undefined'}
{languages.length > 0}
{languages.length:'!0'}

I don't want to have to write an external filter for this as I'm sure it's possible in angular, I'm just not able to get the lingo right.

解决方案

<div ng-repeat="translator in users | filter : { languages : '!!' }">

Explanation:

Consider a list as below:

$scope.items = [
    {
        propertyOne: 'a',
        propertyTwo: 'hello'
    },
    {
        propertyOne: 'b', 
        propertyTwo: null
    },
    {
        propertyOne: 'c', 
        propertyTwo: undefined
    },
    {
        propertyOne: 'd'
    }
];

'!!' filters out objects having a certain property or objects having a certain property that is not undefined or null:

<div ng-repeat="item in items | filter : { propertyTwo : '!!' }">
    {{item.propertyOne}}
</div>
<!-- outputs: a -->

'!' filters out objects not having certain property or objects having a certain property that is undefined or null:

<div ng-repeat="item in items | filter : { propertyTwo : '!' }">
    {{item.propertyOne}}
</div>
<!-- outputs: b c d -->

Plnkr

Note: It does not work for properties with values like 0, false or empty string('').

EDIT: previous answer was different from the plunkr example. I fixed them by swapping '!!' and '!'.

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