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.

• Rayon: What is expected output ?
• Dellirium: There are no associative arrays in javascript, thus you cannot store anything into arr['firstname'] as it is.
• Gerardo Furtado: @Dellirium, the OP can store data using his code: If you use a named index, JavaScript will redefine the array to a standard object.

Answer 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);

Answer 2

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);

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

Answer 3

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]));

• Craicerjack: did you check your own code. Youre adding all combos of name and surname together.
• gurvinder372: @Craicerjack yes, that is what I though OP asked for.
• gurvinder372: @Craicerjack OP said surnames will be distributed to all firstnames
• Lhan Samson: Exactly the output I wanted. Thanks!