检查数组是否包含另一个数组的所有元素

Question

I want a function that returns true if and only if a given array includes all the elements of a given "target" array. As follows.

const target = [ 1, 2, 3,    ];
const array1 = [ 1, 2, 3,    ]; // true
const array2 = [ 1, 2, 3, 4, ]; // true
const array3 = [ 1, 2,       ]; // false

How can I accomplish the above result?

Answer 1

You can combine the .every() and .includes() methods:

 let array1 = [1,2,3], array2 = [1,2,3,4], array3 = [1,2]; let checker = (arr, target) => target.every(v => arr.includes(v)); console.log(checker(array2, array1)); // true console.log(checker(array3, array1)); // false

Answer 2

The every() method tests whether all elements in the array pass the test implemented by the provided function. It returns a Boolean value. Stands to reason that if you call every() on the original array and supply to it a function that checks if every element in the original array is contained in another array, you will get your answer. As such:

 const ar1 = ['a', 'b']; const ar2 = ['c', 'd', 'a', 'z', 'g', 'b']; if(ar1.every(r => ar2.includes(r))){ console.log('Found all of', ar1, 'in', ar2); }else{ console.log('Did not find all of', ar1, 'in', ar2); }

Answer 3

You can try with Array.prototype.every() :

The every() method tests whether all elements in the array pass the test implemented by the provided function.

and Array.prototype.includes() :

The includes() method determines whether an array includes a certain element, returning true or false as appropriate.

 var mainArr = [1,2,3]; function isTrue(arr, arr2){ return arr.every(i => arr2.includes(i)); } console.log(isTrue(mainArr, [1,2,3])); console.log(isTrue(mainArr, [1,2,3,4])); console.log(isTrue(mainArr, [1,2]));

Answer 4

I used Purely Javascript.

function checkElementsinArray(fixedArray,inputArray)
{
    var fixedArraylen = fixedArray.length;
    var inputArraylen = inputArray.length;
    if(fixedArraylen<=inputArraylen)
    {
        for(var i=0;i<fixedArraylen;i++)
        {
            if(!(inputArray.indexOf(fixedArray[i])>=0))
            {
                return false;
            }
        }
    }
    else
    {
        return false;
    }
    return true;
}

console.log(checkElementsinArray([1,2,3], [1,2,3]));
console.log(checkElementsinArray([1,2,3], [1,2,3,4]));
console.log(checkElementsinArray([1,2,3], [1,2]));

Answer 5

If you are using ES5, then you can simply do this.

targetArray =[1,2,3]; 
array1 = [1,2,3]; //return true
array2 = [1,2,3,4]; //return true
array3 = [1,2] //return false

console.log(targetArray.every(function(val) { return array1.indexOf(val) >= 0; })); //true
 console.log(targetArray.every(function(val) { return array2.indexOf(val) >= 0; })); // true
 console.log(targetArray.every(function(val) { return array3.indexOf(val) >= 0; }));// false

Answer 6

I had a similar question but not with two simple arrays. I wanted to check if all items from my array groceryList were included in the basket array consisting of fruit objects.

It checks for every groceryList item weather its value is in some fruit object property fruitType from my basket array.

Maybe this helps someone looking for a solution as I did.

 const groceryList = [ "apple", "cherry"] const basket = [{fruitType: "apple", amount: 3}, {fruitType: "cherry", amount: 20}, {fruitType: "blueberry", amount: 50}] console.log(groceryList, basket, groceryList.every(v => basket.some(w => w.fruitType === v)));

Answer 7

The below does the contains logic:

function contains($superset, $subset) {
    foreach ($subset as $item) if (!in_array($item, $superset)) return true;
    return false;
}

Answer 8

Maybe it will help you, I have this method to validate if an object has a specific attribute

 function existFields(data: object, fields: string[]): boolean { return !fields .map((field) => Object.keys(data).includes(field)) .includes(Boolean(0)); } const data={"test":"a","test2":"b"}; const fields=["test"] console.log(existFields(data,fields))//True console.log(existFields(data,["test","test3"]))//False

 https://stackoverflow.com/questions/53606337/check-if-array-contains-all-elements-of-another-array#

Answer 9

reduce can be used here as well (but it has O = (N * M) difficulty):

const result = target.reduce((acc, el) => {
    return acc && array.includes(el)
}, true);

To solve this in more efficient way(O = N + M):

const myMap = new Map();

array.forEach(element => myMap.set(element);

const result = target.reduce((acc, el) => {
   return acc && myMap.has(el)
}, true);