Question

var work={
    "title": ["test1", "test2"]

}

for(var x in work)
console.log(work.title[x]);

为什么它在控制台中显示未定义

Answer 1

var work = {
  "title": ["internship", "test"],
  "employer": ["sdc", "test"],
  "date": [2017, 2018],
  "location": ["Bouira", "Alger"],
  "description": ["Réalisation logiciel gestion park", "test"]
}

    // for...in
for (var key in work) {
  var value = work[key];
  console.log(value, '\n');

      // for...of
  for (var item of value) {
    console.log(item, '\n\n');
  }
}

Answer 2

您可能希望单独列出test1和test2，在这种情况下，以下内容可行：

for (var x in work["title"]) console.log(work["title"][x]);

Answer 3

您的title工作正常，因此for(var x in work)会重复title，因此会打印["test1", "test2"]

var work={ 
    "title": ["test1", "test2"]
}

for(var x in work) {
    console.log(work[x]);
}

Answer 4

如果您需要打印标题，您应该：

var work = {
    "title": ["test1", "test2"]
}

for (var title of work.title) {
    console.log(title);
}

或者：

var work = {
    "title": ["test1", "test2"]
}

work.title.forEach(function(title) {
    console.log(title);
});

我猜这些是更简洁的javascript方式，在大多数情况下你并不需要使用数组索引。

Answer 5

没有人提到for (... of ...)给我们的价值而不是指数

＆＃13;

let work = {'title': ['test1', 'test2']}

for (let x of work.title) {
  console.log(x);
}

＆＃13;

打印json数据给我未定义

5 个答案: