在数组上查找对象的索引[重复]

Question

我想搜索一个对象数组以找到特定 id 的索引。让我们看看：

这是我的对象数组：

var sentences = [0,
{ id: "1-1", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined },
{ id: "1-2", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined },
{ id: "1-3", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined },
{ id: "2-1", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined },
{ id: "2-2", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined },
{ id: "2-3", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined },
];

例如，我想找到id: "2-1" 的索引，即4。我该怎么做？

我尝试过这样的一些方法，但没有任何成功......

pos = sentences.map(function(e) { return e.sentences.id; }).indexOf('2-1');
console.log(pos)

Answer 1

这里最好的方法是使用findIndex()

var sentences = [0, { id: "1-1", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined }, { id: "1-2", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined }, { id: "1-3", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined }, { id: "2-1", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined }, { id: "2-2", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined }, { id: "2-3", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined }, ];
const res = sentences.findIndex(x => x.id === "2-1");
console.log(res)

您的方法中的问题是您从map() 返回e.sentences.id，这将给出错误。你只需要返回e.id

pos = sentences.map(function(e) { return e.id; }).indexOf('2-1');

使用箭头函数

pos = sentences.map(e => e.id).indexOf('2-1');

Answer 2

你可以取Array#findIndex并检查值是否为truthy，以防止null不能有属性。

var sentences = [0, { id: "1-1", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined }, { id: "1-2", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined }, { id: "1-3", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined }, { id: "2-1", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined }, { id: "2-2", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined }, { id: "2-3", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined }],
    index = sentences.findIndex(o => o &&  o.id === '2-1');

console.log(index);

Answer 3

此代码将帮助您找到对象和索引。

var sentences = [0,
{ id: "1-1", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined },
{ id: "1-2", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined },
{ id: "1-3", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined },
{ id: "2-1", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined },
{ id: "2-2", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined },
{ id: "2-3", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined },
];

let res = sentences.find((each) => { return each.id == "2-1"});
let index = sentences.indexOf(res);
console.log(res, index);

Answer 4

试试这个（希望前导0是错误的）：

var sentences = [{ id: "1-1", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined },
{ id: "1-2", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined },
{ id: "1-3", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined },
{ id: "2-1", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined },
{ id: "2-2", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined },
{ id: "2-3", layer: ["A1", "A2", "A3", "A4", "A5"], difficulty: 4, track: "end", start: 4, end: 6, accuracy: undefined , accent: undefined, meaning_weight: undefined, shadow_weight: undefined, write_weight: undefined },
];

const elements = sentences.filter(obj => obj.id == "2-1")
console.log(elements.length != 0 ? elements[0] : null)