得到一个数组列表,其中包含参加的类(class)和用户的列表;需要一个输出,通过对类(class)进行分组并计算总用户数来显示参加的用户;
var arrList = [
{ class: 'one', user: 'user1' },
{ class: 'two', user: 'user1' },
{ class: 'two', user: 'user2' },
{ class: 'one', user: 'user3' },
{ class: 'two', user: 'user3' },
{ class: 'three', user: 'user1' },
{ class: 'four', user: 'user1' }
];
// output
[
{ class: 'one', user: [ 'user1', 'user2', 'user3' ], count: 3 },
{ class: 'two', user: [ 'user1', 'user3' ], count: 2 },
{ class: 'three', user: [ 'user1' ], count: 1 },
{ class: 'four', user: [ 'user1' ], count: 1 }
];
最佳答案
使用_.groupBy()
通过class
键收集对象,然后映射到所需的表单。
带有链接的解决方案(需要完全导入 lodash 包):
const arrList = [{"class":"one","user":"user1"},{"class":"two","user":"user1"},{"class":"two","user":"user2"},{"class":"one","user":"user3"},{"class":"two","user":"user3"},{"class":"three","user":"user1"},{"class":"four","user":"user1"}];
const result = _(arrList)
.groupBy('class')
.map((group, key) => ({
class: key,
user: _.map(group, 'user'),
count: group.length
}))
.value();
console.log(result);
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.js"></script>
使用_.flow()
的解决方案(可以从lodash包中导入您需要的内容):
const { flow, partialRight: pr, groupBy, map } = _; // replace with imports in your project
const fn = flow(
pr(groupBy, 'class'),
pr(map, (group, key) => ({
class: key,
user: map(group, 'user'),
count: group.length
}))
);
const arrList = [{"class":"one","user":"user1"},{"class":"two","user":"user1"},{"class":"two","user":"user2"},{"class":"one","user":"user3"},{"class":"two","user":"user3"},{"class":"three","user":"user1"},{"class":"four","user":"user1"}];
const result = fn(arrList);
console.log(result);
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.js"></script>
关于javascript - 使用 lodash/Javascript 对类(class)进行分组并计算用户数量,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/55270892/