如何比较2个数组的相同值,并使用true或false标志将它们保存到第3个数组 [英] How to compare 2 arrays for same value and save them to 3rd array with true or false flags
问题描述
我有2个数组:
var arr1 = [{name:"Option1"},{"name":"Option2"},{"name":"Option3"},{"name":"Option4"},{"name":"Option5"},{"name":"Option6"},{"name":"Option7"},{"name":"Option8"},{"name":"Option9"},{"name":"Option10"}]
var arr2 = [{"name": "Option 2"},{"name": "Option 4"},{"name": "Option 6"},{"name": "Option 8"},{"name": "Option 10"}]
我希望实现的是第三个数组,其中包含来自arr1的所有值,并带有附加标记已标记":true (如果在arr2中找到该值)ELSE 已标记";:假
What I wish to achive is that a 3rd array with all the values from arr1 with additional flag of "marked":true if that value is found in arr2 ELSE "marked": false
我尝试了arry方法的各种组合,例如map(),filter(),forEach(),但是以某种方式无法弄清楚如何在不重复值或重复条目的情况下正确返回.
I tried a various combination of arry methods such as map(), filter(), forEach() but somehow not able to figure out how to return properly without repeating the values or making duplicate entries.
**我看到的是我的内部和外部循环都执行了两个语句,并且以某种方式错过了返回真/假逻辑,最终以等于arr2长度的时间重复了我的循环.**
** What I see is that my inside and outside loop both statements are executed and I somehow miss the return true / false logic and end up repeating my loop the number of time equal to the length of arr2. **
function test() {
var arr1 = [{
name: "Option1"
},
{
"name": "Option2"
},
{
"name": "Option3"
},
{
"name": "Option4"
},
{
"name": "Option5"
},
{
"name": "Option6"
},
{
"name": "Option7"
},
{
"name": "Option8"
},
{
"name": "Option9"
},
{
"name": "Option10"
}
]
var arr2 = [{
"name": "Option2"
},
{
"name": "Option4"
},
{
"name": "Option6"
},
{
"name": "Option8"
},
{
"name": "Option10"
}
]
arr1.forEach((el) => {
arr2.forEach((el2) => {
if (el.name.toString() === el2.name.toString()) {
return console.log("Printing from inside the if loop", el)
}
console.log("Printing from outside the if loop", el)
})
})
}
test()
推荐答案
Start by mapping all the comparison values (name) from arr2 into a Set.
然后映射 arr1
来创建新数组并在arr2 Set中查找每个名称
Then map arr1
to create the new array and lookup each name in the arr2 Set
const arr2Names = new Set(arr2.map(e => e.name));
const res = arr1.map(e => ({...e, marked: arr2Names.has(e.name)}));
console.log(res)
<script>
var arr1=[{name:"Option1"},{name:"Option2"},{name:"Option3"},{name:"Option4"},{name:"Option5"},{name:"Option6"},{name:"Option7"},{name:"Option8"},{name:"Option9"},{name:"Option10"}],
arr2=[{name:"Option2"},{name:"Option4"},{name:"Option6"},{name:"Option8"},{name:"Option10"}];
</script>
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