How can you utilize JavaScript to access arrays contained within objects?

Question

How can you utilize JavaScript to access arrays contained within objects?

Imagine we have a JSON stored in a variable named response:

{
    "brands": {
        "Honda": [
          "Accord",
          "Civic"
        ],

        "Porsche": [
          "Cayenne",
          "Cayman"
        ]
    }
}

We want to retrieve the models within each brand. For instance:

for ( var car_brands in response.brands ) {
    console.log(car_brands); // would print Honda, Porsche etc.
}

How can we iterate through car_brands and also obtain the models (arrays) inside each one like Accord, Civic, etc. at the same time?

Perhaps a well-structured JSON format could simplify this parsing process.

javascript json

Answer 1

Answer №1

To access the value, utilize the property indexer syntax like this:

var car_brandsArray = response.brands[car_brands]

Next, iterate through them using a for loop:

for ( var car_brands in response.brands ) {
    console.log(car_brands); // will log Honda, Porsche etc.
    var car_brandsArray = response.brands[car_brands];
    for (var i = 0; i < car_brandsArray .length; i++) {
        console.log(car_brandsArray[i]); // will log Accord, Civi
    }
}

Alternatively, you can directly log the array:

for ( var car_brands in response.brands ) {
        console.log(car_brands); // will log Honda, Porsche etc.
        var car_brandsArray = response.brands[car_brands];
        console.log(car_brandsArray);
    }

Answer 2

To access the value, utilize the property indexer syntax like this:

var car_brandsArray = response.brands[car_brands]

Next, iterate through them using a for loop:

for ( var car_brands in response.brands ) {
    console.log(car_brands); // will log Honda, Porsche etc.
    var car_brandsArray = response.brands[car_brands];
    for (var i = 0; i < car_brandsArray .length; i++) {
        console.log(car_brandsArray[i]); // will log Accord, Civi
    }
}

Alternatively, you can directly log the array:

for ( var car_brands in response.brands ) {
        console.log(car_brands); // will log Honda, Porsche etc.
        var car_brandsArray = response.brands[car_brands];
        console.log(car_brandsArray);
    }

Answer 3

Answer №2

When looping through:

for(var vehicle_brands in response.brands) {
}

You are actually iterating through the indexes (in objects) rather than the values (for in loops through properties).

To retrieve the array:

for(var vehicle_brand in response.brands) {
    var car_vehicle = response.brands[vehicle_brand];
}

To iterate through its values:

for(var vehicle_brand in response.brands) {
    var car_vehicle = response.brands[vehicle_brand];
    for(var index = 0; index < car_vehicle.length; i++) {
        //perform any actions on car_vehicle[index] here;
    }
}

Answer 4

When looping through:

for(var vehicle_brands in response.brands) {
}

You are actually iterating through the indexes (in objects) rather than the values (for in loops through properties).

To retrieve the array:

for(var vehicle_brand in response.brands) {
    var car_vehicle = response.brands[vehicle_brand];
}

To iterate through its values:

for(var vehicle_brand in response.brands) {
    var car_vehicle = response.brands[vehicle_brand];
    for(var index = 0; index < car_vehicle.length; i++) {
        //perform any actions on car_vehicle[index] here;
    }
}

Answer 5

Answer №3

for ( var car_brands in response.brands ) {
    for(var model in response.brands[car_brands]) {
        console.log(model);
    }
}

You were so close, just needed an additional loop :)

Alternatively, you can achieve it using Array.forEach:

response.brands.forEach(function (brand) {
    brand.forEach(function (model) {
        console.log(model);
    });
});

My personal preference is the Array.forEach method.

Answer 6

for ( var car_brands in response.brands ) {
    for(var model in response.brands[car_brands]) {
        console.log(model);
    }
}

You were so close, just needed an additional loop :)

Alternatively, you can achieve it using Array.forEach:

response.brands.forEach(function (brand) {
    brand.forEach(function (model) {
        console.log(model);
    });
});

My personal preference is the Array.forEach method.

How can you utilize JavaScript to access arrays contained within objects?

Answer №1

Answer №2

Answer №3

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