ng-option 有数组，对象两种情况，但目前只接触过数组
数组:
label for value in array
分为一般数组和对象数组
一般数组:
<select ng-model="myAddress" ng-options="item for item in address"></select>
$scope.address= ["北京", "天津", "河北"];
发现第一项为空
dom树如下:
解析: 1.当未设置初始值时，初始值及option列表第一项为空，默认第一项被选 2.value等于label
设置初始值方法:
1.$scope.myAddress= $scope.address[0];
注: 初始值必须得是数组中的某一项，否则无效
则变为:
2.新增option
<select ng-model="myAddress" ng-options="item for item in address">
<option value="" disabled="">请选择地址</option>
</select>
(值得一提的是这种方法只能新增一个option，多写的不会出现)
变为:
disable的option会变为不可选的灰色，此种方法应用面更广
对象数组:
<select ng-model="myColor1" ng-options="color.name for color in colors"></select>
$scope.colors = [
{name:'black', shade:'dark'},
{name:'white', shade:'light', notAnOption: true},
{name:'red', shade:'dark'},
{name:'blue', shade:'dark', notAnOption: true},
{name:'yellow', shade:'light', notAnOption: false}];
dom树如下:
解析: 写法与一般数组不同，value为label所属的对象
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label group by group for value in array（选项分组）
<select ng-model="myColor2" ng-options="color.name group by color.shade for color in colors"></select>
label 分组依据属性
$scope.colors = [
{name:'black', shade:'dark'},
{name:'white', shade:'light', notAnOption: true},
{name:'red', shade:'dark'},
{name:'blue', shade:'dark', notAnOption: true},
{name:'yellow', shade:'light', notAnOption: false}
];
可见按照shade属性进行了分组
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label disable when disable for value in array（将部分option设为disable）
<select ng-model="myColor3" ng-options="color.name disable when color.notAnOption for color in colors"></select>
label disable依据属性
$scope.colors = [
{name:'black', shade:'dark'},
{name:'white', shade:'light', notAnOption: true},
{name:'red', shade:'dark'},
{name:'blue', shade:'dark', notAnOption: true},
{name:'yellow', shade:'light', notAnOption: false}
];
可以看出当notAnOption未false时不可点击
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select as label for value in array（设置value）
<select ng-model="myColor4" ng-options="color.shade as color.name for color in colors"></select>
value label
可见shade成了value，name成了label
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