Javascript 从具有值的 JSON 对象中获取索引
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get index from a JSON object with value
提问by Tismon Varghese
This is my json string.
这是我的 json 字符串。
[{
"name": "placeHolder",
"section": "right"
}, {
"name": "Overview",
"section": "left"
}, {
"name": "ByFunction",
"section": "left"
}, {
"name": "Time",
"section": "left"
}, {
"name": "allFit",
"section": "left"
}, {
"name": "allbMatches",
"section": "left"
}, {
"name": "allOffers",
"section": "left"
}, {
"name": "allInterests",
"section": "left"
}, {
"name": "allResponses",
"section": "left"
}, {
"name": "divChanged",
"section": "right"
}]
Now, i have the value allInterestsand i want to find out the index (this case; it is '7') of this object in the above string. I tried the following code; but it always returns -1. Can someone help me to findout where i went wrong ?
现在，我有了这个值allInterests，我想在上面的字符串中找出这个对象的索引（这种情况下，它是“7”）。我尝试了以下代码；但它总是返回-1。有人可以帮我找出我出错的地方吗？
var q = MY_JSON_STRING
console.log(q.indexOf( 'allInterests' ) );
Thanks and regards, Tismon Varghese
谢谢和问候，蒂斯蒙·瓦格塞
回答by Rajesh
You will have to use Array.findor Array.filteror Array.forEach.
您将不得不使用Array.find或Array.filter或Array.forEach。
Since you value is array and you need position of element, you will have to iterate over it.
由于您的值是数组并且您需要元素的位置，因此您必须对其进行迭代。
Array.find
数组查找
var data = [{"name":"placeHolder","section":"right"},{"name":"Overview","section":"left"},{"name":"ByFunction","section":"left"},{"name":"Time","section":"left"},{"name":"allFit","section":"left"},{"name":"allbMatches","section":"left"},{"name":"allOffers","section":"left"},{"name":"allInterests","section":"left"},{"name":"allResponses","section":"left"},{"name":"divChanged","section":"right"}];
var index = -1;
var val = "allInterests"
var filteredObj = data.find(function(item, i){
if(item.name === val){
index = i;
return i;
}
});
console.log(index, filteredObj);Array.findIndex() @Ted Hopp's suggestion
Array.findIndex() @ Ted Hopp的建议
var data = [{"name":"placeHolder","section":"right"},{"name":"Overview","section":"left"},{"name":"ByFunction","section":"left"},{"name":"Time","section":"left"},{"name":"allFit","section":"left"},{"name":"allbMatches","section":"left"},{"name":"allOffers","section":"left"},{"name":"allInterests","section":"left"},{"name":"allResponses","section":"left"},{"name":"divChanged","section":"right"}];
var val = "allInterests"
var index = data.findIndex(function(item, i){
return item.name === val
});
console.log(index);Default Array.indexOf()will match searchValue to current element and not its properties. You can refer Array.indexOf - polyfillon MDN
默认Array.indexOf()将 searchValue 匹配到当前元素而不是它的属性。你可以参考MDN 上的Array.indexOf - polyfill
回答by Sarat Chandra
You can use Array.findIndex.
您可以使用 Array.findIndex。
var data= [{
"name": "placeHolder",
"section": "right"
}, {
"name": "Overview",
"section": "left"
}, {
"name": "ByFunction",
"section": "left"
}, {
"name": "Time",
"section": "left"
}, {
"name": "allFit",
"section": "left"
}, {
"name": "allbMatches",
"section": "left"
}, {
"name": "allOffers",
"section": "left"
}, {
"name": "allInterests",
"section": "left"
}, {
"name": "allResponses",
"section": "left"
}, {
"name": "divChanged",
"section": "right"
}];
var index = data.findIndex(obj => obj.name=="allInterests");
console.log(index);Hope it helps :)
希望能帮助到你 ：）
回答by void
Traverse through the array and find the index of the element which contains a key nameand has the value as the passed param.
遍历数组并找到包含键name并具有作为传递参数的值的元素的索引。
var data = [{
"name": "placeHolder",
"section": "right"
}, {
"name": "Overview",
"section": "left"
}, {
"name": "ByFunction",
"section": "left"
}, {
"name": "Time",
"section": "left"
}, {
"name": "allFit",
"section": "left"
}, {
"name": "allbMatches",
"section": "left"
}, {
"name": "allOffers",
"section": "left"
}, {
"name": "allInterests",
"section": "left"
}, {
"name": "allResponses",
"section": "left"
}, {
"name": "divChanged",
"section": "right"
}];
Array.prototype.getIndexOf = function(el) {
var arr = this;
for (var i=0; i<arr.length; i++){
console.log(arr[i].name);
if(arr[i].name==el){
return i;
}
}
return -1;
}
alert(data.getIndexOf("allResponses"));回答by GMK Hussain
Function base solution for get index from a JSON object with value by VanillaJS.
VanillaJS 从具有值的 JSON 对象获取索引的函数基础解决方案。
Exemple: https://codepen.io/gmkhussain/pen/mgmEEW
示例：https: //codepen.io/gmkhussain/pen/mgmEEW
var data= [{
"name": "placeHolder",
"section": "right"
}, {
"name": "Overview",
"section": "left"
}, {
"name": "ByFunction",
"section": "left"
}, {
"name": "Time",
"section": "left"
}, {
"name": "allFit",
"section": "left"
}, {
"name": "allbMatches",
"section": "left"
}, {
"name": "allOffers",
"section": "left"
}, {
"name": "allInterests",
"section": "left"
}, {
"name": "allResponses",
"section": "left"
}, {
"name": "divChanged",
"section": "right"
}];
// create function
function findIndex(jsonData, findThis){
var indexNum = jsonData.findIndex(obj => obj.name==findThis);
//Output of result
document.querySelector("#output").innerHTML=indexNum;
console.log(" Array Index number: " + indexNum + " , value of " + findThis );
}
/* call function */
findIndex(data, "allOffers");Output of index number : <h1 id="output"></h1>回答by Saurav
Once you have a json object
一旦你有一个 json 对象
obj.valueOf(Object.keys(obj).indexOf('String_to_Find'))
回答by Jesús Gabriel Banda Durán
In all previous solutions, you must know the name of the attribute or field. A more generic solution for any attribute is this:
在之前的所有解决方案中，您必须知道属性或字段的名称。对于任何属性，更通用的解决方案是：
let data =
[{
"name": "placeHolder",
"section": "right"
}, {
"name": "Overview",
"section": "left"
}, {
"name": "ByFunction",
"section": "left"
}, {
"name": "Time",
"section": "left"
}, {
"name": "allFit",
"section": "left"
}, {
"name": "allbMatches",
"section": "left"
}, {
"name": "allOffers",
"section": "left"
}, {
"name": "allInterests",
"section": "left"
}, {
"name": "allResponses",
"section": "left"
}, {
"name": "divChanged",
"section": "right"
}]
function findByKey(key, value) {
return (item, i) => item[key] === value
}
let findParams = findByKey('name', 'allOffers')
let index = data.findIndex(findParams)
