对象键值切换的Javascript方式

如何解决对象键值切换的Javascript方式

所以我有这份作业，我被困在这一部分。基本上我的数据是这样的

const universities = [
  {
    School: 'Harvard',Country: ['USA']
  },{
    School: 'Oxford',Country: ['UK']
  },{
    School: 'MIT',{
    School: 'Cambridge',{
    School: 'IS',Country: ['Germany','UK','USA']
  },{
    School: 'BIT',Country: ['Germany']
  },]

我正在寻找的输出就是这样

const countryOfOperation = {
    Germany: ['IS','BIT'],UK: ['Oxford','Cambridge','IS'],USA: ['Harvard','MIT','IS']
  }

我能够解决它，但是我的功能看起来真的很糟糕。

const reverse = (universities) => {
  let arr = universities;
  let obj = {};
  let arrs = [];

  arr.forEach((el) => {
    if (!el.Country) return;
    el.Country.forEach((els) => {
      if (arrs.includes(els)) return;
      arrs.push(els);
    });
  });
  arrs.forEach((country) => {
    let countryArr = [];
    arr.forEach((el) => {
      if (!el.Country) return;
      el.Country.find((selected) => {
        if (selected === country) {
          countryArr.push(el.School);
          obj[selected] = countryArr;
        }
      });
    });
  });  
  return obj;
};

有人可以帮助我修复我的代码吗？我会很感激的。我已经花了太多时间在做这个，我很紧张。

解决方法

我建议仅将一个对象作为结果，因为数组中只有一个项目。

基本上，您需要两个嵌套循环，一个用于universities的项目，另一个用于Country的项目。

如果属性country不存在，则需要再次检查。在这种情况下，请为属性分配一个空数组。

最后将School推到属性。

const
    universities = [{ School: 'Harvard',Country: ['USA'] },{ School: 'Oxford',Country: ['UK'] },{ School: 'MIT',{ School: 'Cambridge',{ School: 'IS',Country: ['Germany','UK','USA'] },{ School: 'BIT',Country: ['Germany'] }],countryOfOperation = universities.reduce((accumulator,{ School,Country }) => {
        Country.forEach(country => {
            if (!accumulator[country]) accumulator[country] = [];
            accumulator[country].push(School);
        });
        return accumulator;
    },{});

console.log(countryOfOperation);

.as-console-wrapper { max-height: 100% !important; top: 0; }

,

使用Array#reduce从空对象开始累积所需的结果对象。将国家/地区作为每个对象，并用Array#forEach对其进行迭代。查看累积对象中是否存在该国家/地区的属性。如果不是，则创建一个并添加一个以School为元素的数组。否则，请使用此属性并将School作为新元素添加到数组中。

const universities = [
  {
    School: 'Harvard',Country: ['USA']
  },{
    School: 'Oxford',Country: ['UK']
  },{
    School: 'MIT',{
    School: 'Cambridge',{
    School: 'IS','USA']
  },{
    School: 'BIT',Country: ['Germany']
  },];

let res = universities.reduce((acc,{School,Country}) => {
    Country.forEach(cnt => {
        if (acc[cnt]===undefined) {
            acc[cnt] = [School];
        } else 
            acc[cnt].push(School);
    });
    return acc;
},{});

console.log(res);

,

我认为它可能像下面这样简单：

@api_view(['POST'])
@permission_classes([IsAuthenticated])
def add_comment_likes(request,**kwargs):
    comment_liked = get_object_or_404(PostComment,pk=kwargs.get('i_pk'))
    if comment_liked.likes.filter(pk=request.user.i_pk).exists():
        comment_liked.likes.remove(request.user)
        data = PostCommentSerializer(comment_liked,many=False)
        return Response({'status': status.HTTP_200_OK,'data':data.data})
    else:
        comment_liked.likes.add(request.user)
        data = PostCommentSerializer(comment_liked,'data':data.data})