多重for循环问题
多重for循环问题
提问于 2020-05-25 04:33:53
我有两个数组键和subGrps。
使用这两种方法创建具有将键映射到subGrps数组的新数组。
var keys = ["Subgroup", "0-3", "3-10", "11-40"];
var subGrps = ["SP_20k", "SP_40k", "SP_60k"];
var arrayOfObjects = [];
subGrps.forEach(function(id) {
keys.forEach(function(item) {
if (item === "Subgroup") {
arrayOfObjects.push({
[item]: id
});
} else {
arrayOfObjects.push({
[item]: ""
});
}
});
});
console.log(arrayOfObjects);
预期产出：
[{
"Subgroup" : "SP_20k",
"0-3": "",
"3-10": "",
"11-40": ""
},
{
"Subgroup" : "SP_40k",
"0-3": "",
"3-10": "",
"11-40": ""
},
{
"Subgroup" : "SP_60k",
"0-3": "",
"3-10": "",
"11-40": ""
}]forEach是个好选择吗？对keys array和subGrps array的对象进行分组以获得该输出。
我错过了什么来获得预期的产出？
有人能帮我吗？
回答 6
Stack Overflow用户
回答已采纳
发布于 2020-05-25 04:46:46
可以使用Array.map对subGrps数组进行迭代，创建一个对象，将Subgroup键设置为来自subGrps的值，并使用Object.assign为keys数组中的其他条目添加空值：
var keys = ["Subgroup", "0-3", "3-10", "11-40"];
var subGrps = ["SP_20k", "SP_40k", "SP_60k"];
var arrayOfObjects = subGrps.map(v => Object.assign({
"Subgroup": v
},
...keys.slice(1).map(k => ({
[k]: ""
}))
));
console.log(arrayOfObjects);
这可能会简化为：
var keys = ["Subgroup", "0-3", "3-10", "11-40"];
var subGrps = ["SP_20k", "SP_40k", "SP_60k"];
var arrayOfObjects = subGrps.map(v => Object.assign({},
...keys.map(k => ({
[k]: k == 'Subgroup' ? v : ""
}))
));
console.log(arrayOfObjects);
Stack Overflow用户
发布于 2020-05-25 05:03:20
您可以首先创建对象并在循环中添加键。
var keys = ["Subgroup", "0-3", "3-10", "11-40"];
var subGrps = ["SP_20k", "SP_40k", "SP_60k"];
// creates the object with keys once
// you can also use foreach to create this keysObj too.
var keysObj = keys.reduce((resObj, acc) => {
resObj[acc] = ''
return resObj
}, {})
// uses keysObj to generate array of objects
var arrayOfObjects = subGrps.map(subGrp => ({...keysObj, Subgroup: subGrp}))
console.log(arrayOfObjects)Stack Overflow用户
发布于 2020-05-25 04:46:23
尝尝这个,
const arr = [];
subGrps.forEach(subGrp => {
const obj = {}
keys.forEach(key => obj[key] = (key === 'Subgroup') ? subGrp : '' );
arr.push(obj);
})
console.log(arr)页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/61995853
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