dart中地图值的访问列表?
我有这个地图列表,如何从这个地图访问每个索引的“答案”值dart中地图值的访问列表?,dart,Dart,我有这个地图列表,如何从这个地图访问每个索引的“答案”值 var questions = [ { "question": "Whats your favourite color?", "answers": ["Red", "Green", "Yellow"] }, { "question": "Whats your favourite animal?", "answers": ["Tiger", "Elephant", "U
var questions = [
{
"question": "Whats your favourite color?",
"answers": ["Red", "Green", "Yellow"]
},
{
"question": "Whats your favourite animal?",
"answers": ["Tiger", "Elephant", "Unicorn"]
},
{
"question": "Whats your favourite game?",
"answers": ["Tiger", "Elephant", "Unicorn"]
}
];
这只是一个对象列表。您只需通过以下方式访问:
questions.forEach((element) {
print(element['answers']);
});
以及打印答案:
questions.forEach((element) {
var answers = element['answers'];
answers.forEach((answer) {
print(answer);
});
});
questions.forEach((元素)=>print(元素['answers'])代码>(\u问题[\u索引++][“答案”]作为列表)[i++]
只是一天的提示。您只需编写answers.forEach(print)
即可,它将自动为每个元素调用print
方法。在第二个代码中获取此错误-没有为类“Object”定义方法“forEach”。-““对象”来自“dart:core”,Tryvar answers=element['answers']作为列表代码>。问题是编译器无法猜测元素['answers']
返回的类型。