How to create an array based on two array

Question

I have an array of object, this array contains differents names.

[ "Foo", "Bar", "Test", "Other" ];

And another array of object

[ { name:"Bar", value: 159 }, { name: "Foo", value: 120 }, { name: "Other", value: 1230 } ]

I need to create an array of them, the new array contains sub array with a size of 2, first index the name and second index the value. The order of the array need to be the same of the first one (array of names).

Like

[ ["Foo", 120], ["Bar", 159], ["Test", undefined], ["Other", 1230] ]

So I try this code, but my output is not correct. The order of name is correct but the order of value is not.

var order = ["Foo", "Bar", "Test", "Other"];
var values = [{ name: "Bar", value: 159 }, { name: "Foo", value: 120 }, { name: "Other", value: 1230 }];

var array = order.map(function(name, i) {
  return [name, (values[i] && values[i].value) ];
})

console.log(array)

Nina Scholz · Accepted Answer · 2019-03-28 11:57:00Z

5

You could take a Map and get the items in the wanted order.

var names = [ "Foo", "Bar", "Test", "Other" ],
    objects = [{ name: "Bar", value: 159 }, { name: "Foo", value: 120 }, { name: "Other", value: 1230 }],
    map = new Map(objects.map(({ name, value }) => [name, value])),
    result = names.map(name => [name, map.get(name)])

console.log(result);

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answered Mar 28, 2019 at 11:57

Nina Scholz

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Comments

Jack Bashford · Accepted Answer · 2019-03-28 12:06:50Z

5

You're nearly there - you just need to find the correct value:

var order = ["Foo", "Bar", "Test", "Other"];
var values = [{ name: "Bar", value: 159 }, { name: "Foo", value: 120 }, { name: "Other", value: 1230 }];

var array = order.map(function(name, i) {
  return [name, values.some(e => e.name == name) ? values.find(e => e.name == name).value : undefined];
})

console.log(array)

ES5 syntax:

var order = ["Foo", "Bar", "Test", "Other"];
var values = [{ name: "Bar", value: 159 }, { name: "Foo", value: 120 }, { name: "Other", value: 1230 }];

var array = order.map(function(name, i) {
  return [name, values.some(function(e) { 
    return e.name == name;
  }) ? values.find(function(e) {
    return e.name == name;
  }).value : undefined];
});

console.log(array)

edited Mar 28, 2019 at 12:06

answered Mar 28, 2019 at 11:54

Jack Bashford

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Comments

lankovova · Accepted Answer · 2019-03-28 11:55:25Z

4

Check out my solution. Hope this helps.

const a = [ "Foo", "Bar", "Test", "Other" ];
const b = [ { name:"Bar", value: 159 }, { name: "Foo", value: 120 }, { name: "Other", value: 1230 } ];

const res = a.map((item) => [ item, (b.find(({ name }) => name === item) || {}).value ])

console.log(res)

answered Mar 28, 2019 at 11:55

lankovova

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1 Comment

georg Over a year ago

Note that name === item is invoked len(a) x len(b) times - this might or might not matter, depending on how large they are.

Jaromanda X · Accepted Answer · 2019-03-28 11:56:02Z

4

You need to use entries in "order" to lookup "name" in values

var order = ["Foo", "Bar", "Test", "Other"];
var values = [{ name: "Bar", value: 159 }, { name: "Foo", value: 120 }, { name: "Other", value: 1230 }];

var array = order.map(function(key, i) {
  let found = values.find(({name}) => name === key);
  return [key, found && found.value ];
})

console.log(array)

answered Mar 28, 2019 at 11:56

Jaromanda X

1

Comments

baao · Accepted Answer · 2019-03-28 11:56:43Z

3

You could use map and take the Object.values of the found item, or a default one

const arr1 = [ "Foo", "Bar", "Test", "Other" ];

const arr2 = [ { name:"Bar", value: 159 }, { name: "Foo", value: 120 }, { name: "Other", value: 1230 } ];

const res = arr1.map(e => Object.values(arr2.find(({name}) => name === e) || ({name: e, value: undefined})));
console.log(res);

answered Mar 28, 2019 at 11:56

baao

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Comments

Seenuvasan Velayutham · Accepted Answer · 2019-03-28 12:26:42Z

1

var order = ["Foo", "Bar", "Test", "Other"];
var values = [{ name: "Bar", value: 159 }, { name: "Foo", value: 120 }, { name: "Other", value: 1230 }];
var result = [];
orders.forEach((f) => {
let found = false;

values.forEach(s => {
    if (f === s.name) {
result.push([f, s.value]);
        found = true;
}
});
if (!found) {
    result.push([f, undefined]);
}
});

edited Mar 28, 2019 at 12:26

answered Mar 28, 2019 at 12:21

Seenuvasan Velayutham

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