获取JSON的长度，角度

{ "questions": [ 
    { 
    "text": "Which colors do you see in the rainbow?", 
    "answer": "A", 
    "A": "RED", 
    "B": "ORANGE", 
    "C": "YELLOW", 
    "D": "GREEN" 
}, 
{ 
    "text": "What is sanatbek's family name?", 
    "answer": "C", 
    "A": "Saidov", 
    "B": "Muhammadlatipov", 
    "C": "Matlatipov", 
    "D": "Boboyev" 
}, 
{ 
    "text": "How many members does this company have?", 
    "answer": "C", 
    "A": "3", 
    "B": "8", 
    "C": "9", 
    "D": "2" 
} 
] 
}

这是我JSON文件，我需要得到的问题长度AngularJS这样的：获取JSON的长度，角度

function getQuestionCount() { 
    return $scope.questions.length; 
}

这里$scope.questions在控制器中声明：我尝试了好几种像

return Object.keys($scope.questions).length这是returning value: 6;显示后console.log($scope.questions)。我明白这是我的Parsed Object的属性数量。
然后想了一下，我试了这return $scope.questions.data.questions.length;这是工作。但是，以下错误显示在我的控制台上。

这里是我的错误消息：

Error message

TypeError: Cannot read property 'data' of undefined.

来源

2017-10-28 mr.sanatbek

什么是'$ scope.questions'？它是三个对象的数组吗？ –

是的，它应该是从'questions'键取得的三个对象的数组。 Raghu先生的解决方案是解决我的问题的答案。 –

从您共享可以理解的，你做了一个HTTP GET调用来检索数据的屏幕截图。成功完成通话后，您可以在范围内的变量中设置问题长度。

$http({ 
    method: 'GET', 
    url: '/someUrl' 
}).then(function successCallback(response) { 
    $scope.questionsLenght = response.data.questions.length; 
    }, function errorCallback(response) { 
    // called asynchronously if an error occurs 
    // or server returns response with an error status. 
    });

来源

2017-10-28 07:29:15 Raghu

谢谢。当我从JSON解析出来的时候，我用全部的'response'来代替'response.data.questions'给我的全局变量！ –

您可以通过使用for循环获取长度：

for (var i = 0; i < $scope.questions.length; i++) { 
    $scope.data.push(angular.copy(types[i])); 
    }

来源

2017-10-28 07:23:40

如果你的控制器，你设置你的JSON字符串

$scope.questions = { 
    "questions": [ 
    { 
     "text": "Which colors do you see in the rainbow?", 
     "answer": "A", 
     "A": "RED", 
     "B": "ORANGE", 
     "C": "YELLOW", 
     "D": "GREEN" 
    }, 
{ 
    "text": "What is sanatbek's family name?", 
    "answer": "C", 
    "A": "Saidov", 
    "B": "Muhammadlatipov", 
    "C": "Matlatipov", 
    "D": "Boboyev" 
}, 
{ 
    "text": "How many members does this company have?", 
    "answer": "C", 
    "A": "3", 
    "B": "8", 
    "C": "9", 
    "D": "2" 
} 
    ] 
};

尝试

$scope.questions.questions.length;

为您的JSON字符串数组里的名字是问题

来源

2017-10-28 07:24:48 NTP

获取JSON的长度，角度

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