Nested Multidimension Array in Javascript

Question

Given this code:

<script type="text/javascript">
    var arr = [];
    var names = [{name : 'George'}, {name : 'Ringo'}, {name : 'Paul'}, {name : 'John'}];
    var surnames = [{surname : 'Harrison'}, {surname : 'Starr'}, {surname : 'McCartney'}, {surname : 'Lennon'}];

    for (i = 0; i < names.length; i++) {
            arr['firstname'] = names[i];
        for (j = 0; j < surnames.length; j++) {
            arr['firstname']['surname'] = surnames[j];
            arr['firstname']['surname']['index'] = i;
            console.log(arr);
        }
    }
</script>

When run, output in the inner loop would only show the last value of surnames array(Lennon) and i(3) on all entries. Output I want to achieve is for each name, surnames will be distributed to all firstnames (eg. John Harrison, John Starr, etc.) and index(i) will increment from 0 to 3. Thanks.

There are no associative arrays in javascript, thus you cannot store anything into arr['firstname'] as it is. — Dellirium
– Dellirium, Commented Jun 17, 2016 at 9:57
@Dellirium, the OP can store data using his code: If you use a named index, JavaScript will redefine the array to a standard object. — Gerardo Furtado
– Gerardo Furtado, Commented Jun 17, 2016 at 10:03

Eytibi · Accepted Answer · 2016-06-17 09:59:59Z

1

Do you want something like this?

var arr = [];
var names = [{
  name: 'George'
}, {
  name: 'Ringo'
}, {
  name: 'Paul'
}, {
  name: 'John'
}];
var surnames = [{
  surname: 'Harrison'
}, {
  surname: 'Starr'
}, {
  surname: 'McCartney'
}, {
  surname: 'Lennon'
}];

for (i = 0; i < names.length; i++) {
  arr.push({
      index: i,
      firstname: names[i].name,
      surname: surnames[i].surname
    });
  }
  console.log(arr);

answered Jun 17, 2016 at 9:59

Eytibi

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Comments

rejo · Accepted Answer · 2016-06-17 10:10:39Z

1

Try like this ,

for (i = 0; i < names.length; i++) {
       var obj = new Object;
        obj['name'] = names[i];
        obj['name']['surname'] = surnames[i].surname;
        obj['index'] = i;
        arr.push(obj);

}
   console.log(arr);

edited Jun 17, 2016 at 10:10

answered Jun 17, 2016 at 10:01

rejo

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1 Comment

Rayon Over a year ago

arr['firstname'] is not an object to have a key!

gurvinder372 · Accepted Answer · 2016-06-17 10:06:01Z

0

Looks like you want Cartesian product of all first names with surnames.

try this

 var arr = [];
 var names = [{
   name: 'George'
 }, {
   name: 'Ringo'
 }, {
   name: 'Paul'
 }, {
   name: 'John'
 }];
 var surnames = [{
   surname: 'Harrison'
 }, {
   surname: 'Starr'
 }, {
   surname: 'McCartney'
 }, {
   surname: 'Lennon'
 }];

 for (i = 0; i < names.length; i++) 
 {
   for (j = 0; j < surnames.length; j++) 
   {
     var tmpObj = JSON.parse(JSON.stringify(names[i]));
     tmpObj['surname'] = surnames[j].surname;
     tmpObj['index'] = i;
     arr.push(tmpObj);
   }
 }
 console.log(arr);

Alternatively you can also do

Object.create(names[i])

instead of

JSON.parse(JSON.stringify(names[i]));

edited Jun 17, 2016 at 10:06

answered Jun 17, 2016 at 10:02

gurvinder372

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4 Comments

Craicerjack Over a year ago

did you check your own code. Youre adding all combos of name and surname together.

gurvinder372 Over a year ago

@Craicerjack yes, that is what I though OP asked for.

gurvinder372 Over a year ago

@Craicerjack OP said surnames will be distributed to all firstnames

Lhan Samson Over a year ago

Exactly the output I wanted. Thanks!

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