Loop not gathering all values from array

Question

I am trying to create 2 loops that work one after each other. I am basically trying to get all the fruits from the array. I have tried doing a for loop inside a for loop but that only gives me the first fruit from each object not every single fruit in the array.

var customers = [{
            "Name" : "John",
            "Items" :[
                {"Fruits" : "Apple"},{"Fruits" : "Orange"}]
            },{
                "Name" : "Sam",
            "Items" :[
                {"Fruits" : "Pear"},{"Fruits" : "Nuts"}]
            },{
                "Name" : "Eric",
            "Items" :[
                {"Fruits" : "Banana"},{"Fruits" : "Raisins"}]
            }];
 for(i=0; i<=customers.length; i++){
 for(a=0; a<=customers.length; a++){
     alert(customers[i]["Items"][a]);
 }
}

gurvinder372 · Accepted Answer · 2017-12-12 13:21:31Z

2

Your second for-loop should be items rather than customers

for(i=0; i < customers.length; i++) //notice that i < instead of i <=
{
   for(a=0; a < customers[i].Items.length; a++) //notice the change here
   {
     alert( customers[i].Items[a].Fruits ); // 
   }
}

A little more precise one would be using reduce

var allFruits = customers.reduce( ( a, b ) => a.concat( b.Items.map( s => s.Fruits ) ) , []);

edited Dec 12, 2017 at 13:21

answered Dec 12, 2017 at 13:19

gurvinder372

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2 Comments

George Over a year ago

Also should be i < and a < rather than the i <= and a <=

wertyj Over a year ago

Thank you for your help!

vadzim dvorak · Accepted Answer · 2017-12-12 13:21:42Z

1

Your second loop has an incorrect length. Try this:

    var customers = [{
                "Name" : "John",
                "Items" :[{"Fruits" : "Apple"},{"Fruits" : "Orange"}]
            },{
                "Name" : "Sam",
                "Items" :[{"Fruits" : "Pear"},{"Fruits" : "Nuts"}]
            },{
                "Name" : "Eric",
                "Items" :[{"Fruits" : "Banana"},{"Fruits" : "Raisins"}]
            }];
 for(i=0; i<=customers.length; i++){
    for(a=0; a<=customers[i]["Items"].length; a++){
        alert(customers[i]["Items"][a]);
    }
}

answered Dec 12, 2017 at 13:21

vadzim dvorak

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Comments

Raavan · Accepted Answer · 2017-12-12 13:21:59Z

1

This should solve your issue.

var customers = [{
            "Name" : "John",
            "Items" :[
                {"Fruits" : "Apple"},{"Fruits" : "Orange"}]
            },{
                "Name" : "Sam",
            "Items" :[
                {"Fruits" : "Pear"},{"Fruits" : "Nuts"}]
            },{
                "Name" : "Eric",
            "Items" :[
                {"Fruits" : "Banana"},{"Fruits" : "Raisins"}]
            }];
 for(i=0; i<customers.length; i++){
 for(a=0; a<customers[i]["Items"].length; a++){
     console.log(customers[i]["Items"][a]);
 }
}

answered Dec 12, 2017 at 13:21

Raavan

662 bronze badges

Comments

Mihai Alexandru-Ionut · Accepted Answer · 2017-12-12 13:25:26Z

0

Just use concat method in combination with map and reduce for a easy solution.

let fruits = [].concat(...customers.map(a => a.Items.map(b=>b.Fruits)));

var customers = [{ "Name" : "John", "Items" :[ {"Fruits" : "Apple"},{"Fruits" : "Orange"}] },{ "Name" : "Sam", "Items" :[ {"Fruits" : "Pear"},{"Fruits" : "Nuts"}] },{ "Name" : "Eric", "Items" :[ {"Fruits" : "Banana"},{"Fruits" : "Raisins"}] }];

let fruits = [].concat(...customers.map(a => a.Items.map(b=>b.Fruits)));
console.log(fruits);

If you want to get all unique fruits, you can use Set from ES6.

var customers = [{ "Name" : "John", "Items" :[ {"Fruits" : "Apple"},{"Fruits" : "Orange"}] },{ "Name" : "Sam", "Items" :[ {"Fruits" : "Pear"},{"Fruits" : "Nuts"}] },{ "Name" : "Eric", "Items" :[ {"Fruits" : "Banana"},{"Fruits" : "Raisins"}] }];
let fruits = [...new Set([].concat(...customers.map(a => a.Items.map(b=>b.Fruits))))];
console.log(fruits);

edited Dec 12, 2017 at 13:25

answered Dec 12, 2017 at 13:21

Mihai Alexandru-Ionut

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1 Comment

Rajesh Dixit Over a year ago

Since you are using ES6, you can try [].concat(...customers.map(...))

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