Evaluating the values of one array in comparison to those of another array

Question

Evaluating the values of one array in comparison to those of another array

Exploring arrays and comparing their values. Here is an example of an array with values:

arr1 = [1,5,6,7,3,8,12];

Now we have another array that we want to compare with:

arr2 = [3,5,7];

We need to check if all the values in arr2 are present in arr1.

function containsValue(n){
  for(var i=0; i<this.length; i++){
         if(this[i] == n)
             return true;
  }
  return false;
}

arr1.containsValue("12"); //would work
// How can we efficiently check if arr1 contains all values in arr2?

The current code works for individual numbers, but how can we modify it to handle arrays and efficiently compare them?

javascript arrays

Answer 1

Answer №1

Make sure to expand your array so that you can utilize the function.
When referencing this.length, it pertains to the function and not the array itself.

Feel free to test out the following code.

Array.prototype.equals = function (array, strict) {
    if (!array)
        return false;

    if (arguments.length == 1)
        strict = true;

    if (this.length != array.length)
        return false;

    for (var i = 0; i < this.length; i++) {
        if (this[i] instanceof Array && array[i] instanceof Array) {
            if (!this[i].equals(array[i], strict))
                return false;
        }
        else if (strict && this[i] != array[i]) {
            return false;
        }
        else if (!strict) {
            return this.sort().equals(array.sort(), true);
        }
    }
    return true;
}



var arr1 = [1, 2, 3, 4];
var arr2 = [2, 1, 4, 3];  // Loosely equal to 1
var arr3 = [2, 2, 3, 4];  // Not equal to 1
var arr4 = [1, 2, 3, 4];  // Strictly equal to 1

arr1.equals(arr2);         // false
arr1.equals(arr2, false);  // true
arr1.equals(arr3);         // false
arr1.equals(arr3, false);  // false
arr1.equals(arr4);         // true
arr1.equals(arr4, false);  // true

I trust this information proves beneficial.

Answer 2

Make sure to expand your array so that you can utilize the function.
When referencing this.length, it pertains to the function and not the array itself.

Feel free to test out the following code.

Array.prototype.equals = function (array, strict) {
    if (!array)
        return false;

    if (arguments.length == 1)
        strict = true;

    if (this.length != array.length)
        return false;

    for (var i = 0; i < this.length; i++) {
        if (this[i] instanceof Array && array[i] instanceof Array) {
            if (!this[i].equals(array[i], strict))
                return false;
        }
        else if (strict && this[i] != array[i]) {
            return false;
        }
        else if (!strict) {
            return this.sort().equals(array.sort(), true);
        }
    }
    return true;
}



var arr1 = [1, 2, 3, 4];
var arr2 = [2, 1, 4, 3];  // Loosely equal to 1
var arr3 = [2, 2, 3, 4];  // Not equal to 1
var arr4 = [1, 2, 3, 4];  // Strictly equal to 1

arr1.equals(arr2);         // false
arr1.equals(arr2, false);  // true
arr1.equals(arr3);         // false
arr1.equals(arr3, false);  // false
arr1.equals(arr4);         // true
arr1.equals(arr4, false);  // true

I trust this information proves beneficial.

Answer 3

Answer №2

It seems like your function contains is part of Array.prototype since you are using this.

In this case, you can simply utilize .every() to loop through and check every value in array b.

function contains(n){
  for(var i=0; i<this.length; i++){
         if(this[i] == n)
             return true;
  }
  return false;
}

Array.prototype.contains = contains;

var a = [1,5,6,7,3,8,12];

var b = [3,5,7];

var has_all = b.every(function(val) {
    return a.contains(val);
});

alert(has_all);

The .every() method will stop at the first non-matching value and return true only if all values are found.

ECMScript 5 provides an .indexOf() method, which can be used instead of defining a separate function.

var a = [1,5,6,7,3,8,12];

var b = [3,5,7];

var has_all = b.every(function(val) {
    return a.indexOf(val) !== -1;
});

alert(has_all);

Answer 4

It seems like your function contains is part of Array.prototype since you are using this.

In this case, you can simply utilize .every() to loop through and check every value in array b.

function contains(n){
  for(var i=0; i<this.length; i++){
         if(this[i] == n)
             return true;
  }
  return false;
}

Array.prototype.contains = contains;

var a = [1,5,6,7,3,8,12];

var b = [3,5,7];

var has_all = b.every(function(val) {
    return a.contains(val);
});

alert(has_all);

The .every() method will stop at the first non-matching value and return true only if all values are found.

ECMScript 5 provides an .indexOf() method, which can be used instead of defining a separate function.

var a = [1,5,6,7,3,8,12];

var b = [3,5,7];

var has_all = b.every(function(val) {
    return a.indexOf(val) !== -1;
});

alert(has_all);

Answer 5

Answer №3

Utilize the prototype property to efficiently reuse a function whenever it is required.

Array.prototype.contains = function (n) {
  var s;
    for(s in this){
      if (this.hasOwnProperty(s) && n.indexOf(this[s]) !== -1) {
        return true;
      }
    }
  return false;
};

var numbers1 = [1, 5, 6, 7, 3, 8, 12],
  numbers2 = [1, 2, 11];
console.log(numbers1.contains(numbers2));

Answer 6

Utilize the prototype property to efficiently reuse a function whenever it is required.

Array.prototype.contains = function (n) {
  var s;
    for(s in this){
      if (this.hasOwnProperty(s) && n.indexOf(this[s]) !== -1) {
        return true;
      }
    }
  return false;
};

var numbers1 = [1, 5, 6, 7, 3, 8, 12],
  numbers2 = [1, 2, 11];
console.log(numbers1.contains(numbers2));

Evaluating the values of one array in comparison to those of another array

Answer №1

Answer №2

Answer №3

Similar questions

Distributing Back-end Information to a JavaScript File

Stop the window from scrolling downwards

When the JS function 'postMessage()' is invoked on an HTML object tag, what specific action does it perform?

Issue with JQuery delay functionality not activating correctly upon clicking an <a> tag

Moving from ngRoute to ui-router in AngularJS is causing a [$injector:unpr] error to be thrown

Having trouble triggering a click event on Ant Design menu button using jest and enzyme

When an AJAX request is successful in Angular, utilize the ng-hide directive

hiding form fields using javascript

Leveraging Components within Components in Vue 2

How can I resolve the issue of neglecting the result of `inputstream.read` in IntelliJ?

Issue arises in Vue.js component array misalignment upon substituting with a smaller array

Retrieving selections from a group of checkboxes and managing their addition or removal in an array

Utilize Optional Chaining for verifying null or undefined values

Controlling Fabric in Three.JS

Simple method to modify the text size of the entire HTML page

The Vue design is not being reflected as expected

Move the div containing an <audio></audio> tag

Is it possible for React Server Side rendering to be re-rendered on the client side?

Checking that an object's keys are all present in an array in TypeScript should be a top priority

What is the process for using dojo to load content?