Question

我有这个数组：

items = []
items[0] = {id: "805", category: 'Apple'}
items[1] = {id: "804", category: 'Watermelon'}
items[2] = {id: "804", category: 'Plum'}

和forEach，当我得到category value时。

var result = '';
items.forEach(function(item) {
result += item.category;
});
console.log(result);

但问题是在console.log中我得到了Apple, Watermelon, Plum，这得到了我的结果。我如何在控制台中获得这样的输入 -

Apple
Watermelon
Plum

Answer 1

如果您想添加换行符：

const items = [
  {id: "805", category: 'Apple'},
  {id: "804", category: 'Watermelon'},
  {id: "804", category: 'Plum'}
];

let result = '';
items.forEach(function(item) {
  if (result) result += '\n';
  result += item.category;
});
console.log(result);

但是当迭代数组以在最后生成单个值时，使用.reduce更合适：

const items = [
  {id: "805", category: 'Apple'},
  {id: "804", category: 'Watermelon'},
  {id: "804", category: 'Plum'}
];

const result = items.reduce((resultSoFar, item) => {
  if (resultSoFar) resultSoFar += '\n';
  resultSoFar += item.category;
  return resultSoFar;
}, '');
console.log(result);

Answer 2

在末尾添加'\n'

items = []
items[0] = {id: "805", category: 'Apple'}
items[1] = {id: "804", category: 'Watermelon'}
items[2] = {id: "804", category: 'Plum'}

var result = '';
items.forEach(function(item) {
  result += item.category+'\n';  //add '\n' at the end
});

result=result.substr(0,result.length-1);  // remove last character(which is '\n')
console.log(result);

Answer 3

你必须这样做：

＆＃13;

buildTypes {
        release {
            debuggable false
            minifyEnabled true
            shrinkResources true
            useProguard true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
            signingConfig signingConfigs.release
        }
    }

＆＃13;

Answer 4

＆＃13;

    items = []
    items[0] = {id: "805", category: 'Apple'}
    items[1] = {id: "804", category: 'Watermelon'}
    items[2] = {id: "804", category: 'Plum'}

    var result = '';
    items.forEach(function(item)
    {
      result += item.category + '\r\n';
    });
    
    console.log(result);

＆＃13;

Answer 5

在您的情况下，您将使用map和join的组合。 map创建的数组只包含category的值，而join会将这些值加在一起。

items = [
   {id: "805", category: 'Apple'},
   {id: "804", category: 'Watermelon'},
   {id: "804", category: 'Plum'}
]

var result =  items.map(item => item.category).join('\n')
console.log(result)

Answer 6

    items = []
    items[0] = {id: "805", category: 'Apple'}
    items[1] = {id: "804", category: 'Watermelon'}
    items[2] = {id: "804", category: 'Plum'}


    var result = '';
    items.forEach(function(item) {
        result += item.category;
    });
   console.log(result);

使用上面的代码。错误是dscr属性

麻烦forEach

6 个答案: