CODEWITHSUNDEEP
javascriptarrays
Dreysion
Dreysion

Reputation: 23

Return an array using a value (Javascript)

is it possible to get an array if you only know one of its values?

I've got two arrays and want to find which one has the variable:

var fruit = ["apple","banana","orange"];
var veggie = ["carrot","pea","corn"];
alert("An apple is a " + /*return array with value "apple"*/);

Is it possible to do this with Javascript? Thanks

Upvotes: 1

Views: 58

Answers (5)

Andy
Andy

Reputation: 63587

I would use an object to contains the various types:

var type = {
  fruit: ["apple", "banana", "orange"],
  veggie: ["carrot", "pea", "corn"]
}

If you want to find the name of the array the thing is in loop over the arrays in the object, using indexOf to test for the thing's presence.

function findThing(thing) {
  for (var k in type) {
    if (type[k].indexOf(thing) > -1) return k;
  }
  return 'unknown';
}

console.log('An apple is a ' + findThing('apple')); // An apple is a fruit
console.log('An froom is a ' + findThing('froom')); // An froom is a unknown

Fiddle

On the other hand, if you wanted to return some more information (like the type, size, and other items, you could do this:

function returnArrayOfThing(thing) {
  for (var k in type) {
    if (type[k].indexOf(thing) > -1) return k + ' which contains ' + type[k].length + ' items: ' + type[k];
  }
  return 'unknown';
}

console.log('An apple is in ' + returnArrayOfThing('apple')); // An apple is in fruit which contains 3 items: apple,banana,orange

Upvotes: 0

Suman Bogati
Suman Bogati

Reputation: 6351

Use the object to contain these two arrays like this.

JSFIDDLE

var food = {
    fruit : ["apple","banana","orange"],
    veggie : ["carrot","pea","corn"]
}

var arr = getFood('apple', food);
//returns ["apple","banana","orange"];

 var arr2 = getFood('pea', food);
//returns ["carrot","pea","corn"];

function getFood(item, food){
    for (var key in food){
        if(food[key].indexOf(item) != -1){
            return food[key];
        }
    }
}

Upvotes: 0

Tibos
Tibos

Reputation: 27853

If you only have the two categories, then you can do a simple if check:

var fruit = ["apple","banana","orange"];
var veggie = ["carrot","pea","corn"];

var typeOfApple = 'unknown';

if (fruit.indexOf('apple') !== -1) {
  typeOfApple = 'fruit';
} else if (veggie.indexOf('apple') !== -1) {
  typeOfApple = 'veggie';
}
alert("An apple is a " + typeOfApple);

If you have more categories (or simply want your code to be more robust), you could use an object with keys as categories and values arrays with items from that category:

var types = {
  fruit : ["apple","banana","orange"],
  veggie : ["carrot","pea","corn"]
}

Then you can check every category if it contains your item:

var typeOfApple = 'unknown';

for (var type in types) {
  if (types[type].indexOf('apple') !== -1)
    typeOfApple = type;
}


alert("An apple is a " + typeOfApple);

Upvotes: 0

ltalhouarne
ltalhouarne

Reputation: 4638

You can use a function like below, and call it on each concerned array:

function contains(a, obj) {   //a is the array to check, and obj the object you are looking for
    var i = a.length;
    while (i--) {
       if (a[i] === obj) {
           return true;
       }
    }
    return false;
}

Upvotes: 0

athms
athms

Reputation: 958

Wrap the alert in an if/else statement and check the index of 'apple'. If fruit.indexOf('apple') != -1 then it must be a fruit.

Upvotes: 1

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