i have two array
var a=[
{_id:1,name:'a'},
{_id:2,name:'b'},
{_id:3,name:'c'},
]
var b=[
{key:1,dis:0.5},
{key:2,dis:0.9},
{key:3,dis:10}
]
from this both there is _id and key , what i want is if both _id and key are same than i want one array which look like this
var result=[
{_id:1,name:'a',dis:0.5},
{_id:2,name:'b',dis:0.9},
{_id:3,name:'c',dis:1},
]
NOTE : i don't want to use any _ functions similer like _.map or _.extend
Thanks
Here is a solution with array#find and array#map
var a=[
{_id:1,name:'a'},
{_id:2,name:'b'},
{_id:3,name:'c'},
]
var b=[
{key:1,dis:0.5},
{key:2,dis:0.9},
{key:3,dis:10}
]
var merged = a.map(o => {
let temp = b.find(obj => obj.key === o._id);
let res = Object.assign(o,temp);
delete res.key;
return res;
});
console.log(merged);
array.find instead of array.filter
array.find more often now!You could use a hash table for the same identifier. The hash table contains the new generated objects of the result set.
First, a new object is creted and mapped and also store in the hash table. Then in a second loop over the other array, then missing property is added to the object.
The result is an array with new objects.
var a = [{ _id: 1, name: 'a' }, { _id: 2, name: 'b' }, { _id: 3, name: 'c' }],
b = [{ key: 1, dis: 0.5 }, { key: 2, dis: 0.9 }, { key: 3, dis: 10 }, { key: 4, dis: 42 }],
hash = Object.create(null),
result = a.map(function (o) {
return hash[o._id] = { _id: o._id, name: o.name };
});
b.forEach(function (o) {
if (!hash[o.key]) {
result.push(hash[o.key] = { _id: o.key, name: 'unknown' });
}
hash[o.key].dis = o.dis;
});
console.log(result);.as-console-wrapper { max-height: 100% !important; top: 0; }
Simple use as follows
var result = [];
for(var i = 0; i <= a.length-1; i++){
for(var j = 0; i <= b.length-1; j++){
if(a[i]._id == b[j].key){
result.push(id: a[i]._id, name: a[i].name, dis: b[j].dis)
}
}
}
console.log(result);
Try this:
if (a.length&& b.length) {
for (var i = 0; i < a.length; i++) {
for (var j = 0; j < b.length; j++) {
if (a[i]._id == b[j].key) {
a[i].dis = b[j].dis;
}
}
}
}
console.log(a);
OR
var result = [];
if (a.length&& b.length) {
for (var i = 0; i < a.length; i++) {
var obj = {
_id: a[i]._id,
name: a[i].name,
dis: ""
}
for (var j = 0; j < b.length; j++) {
if (a[i]._id == b[j].key) {
obj.dis = b[j].dis;
}
}
result.push(obj);
}
}
console.log(result);
AFAIK this is O(N) instead of O(N^2) like most of the other answers...
var a = [{
_id: 1,
name: 'a'
}, {
_id: 2,
name: 'b'
}, {
_id: 3,
name: 'c'
}]
var b = [{
key: 1,
dis: 0.5
}, {
key: 2,
dis: 0.9
}, {
key: 3,
dis: 10
}]
function merge(a, b) {
const bKeys = b.reduce((p, c) => (p.set(c.key, c), p), new Map);
return a.map(o=>Object.assign({}, o, bKeys.get(o._id) ));
}
console.log(merge(a, b));
var res = a.map(function(e, i){
e.dis = b.find(function(eb){return eb.key == e._id;}).dis;
return e;
});
// res : [{"_id":1,"name":"a","dis":0.5},{"_id":2,"name":"b","dis":0.9},{"_id":3,"name":"c","dis":10}]
