Skip to content

Algorithm Diff Two Arrays

Quincy Larson edited this page Aug 20, 2016 · 1 revision

Algorithm Diff Two Arrays

🚩 Remember to use Read-Search-Ask if you get stuck. Try to pair program 👥 and write your own code 📝

🏁 Problem Explanation:

Check two arrays and return a new array that contains only the items that are not in either of the original arrays.

Relevant Links

💬 Hint: 1

Merge the list to make it easy to compare functions.

try to solve the problem now

💬 Hint: 2

Use filter to get the new array, you will need to create a callback function.

try to solve the problem now

💬 Hint: 3

The best way to go about the callback function is to check if the number from the new merged array is not in both original arrays and return it.

try to solve the problem now

Spoiler Alert!

687474703a2f2f7777772e796f75726472756d2e636f6d2f796f75726472756d2f696d616765732f323030372f31302f31302f7265645f7761726e696e675f7369676e5f322e676966.gif

Solution ahead!

🔰 Basic Code Solution (Imperative Solution):

function diffArray(arr1, arr2) {
  var newArr = [];
  // Looping through arr1 to find elements that do not exist in arr2  
  for (var i = 0; i < arr1.length; i++) {
    if (arr2.indexOf(arr1[i]) === -1){
      // Pushing the unique to arr1 elements to the newArr
      newArr.push(arr1[i]);
    }
  }
  // Looping through arr2 to find elements that do not exist in arr1
  for (var j = 0; j < arr2.length; j++) {
    if (arr1.indexOf(arr2[j]) === -1){
      // Pushing the unique to arr2 elements to the newArr    
      newArr.push(arr2[j]);
    }
  }

  return newArr;
}

diffArray([1, 2, 3, 5], [1, 2, 3, 4, 5]);

Run Code 🚀

Code Explanation:

Read the comments in the code.

Relevant Links

🌻 Intermediate Code Solution (Declarative Solution):

function diffArray(arr1, arr2) {
  return arr1
    .concat(arr2)
    .filter(
        item => !arr1.includes(item) || !arr2.includes(item)
    )
}

diffArray([1, 2, 3, 5], [1, 2, 3, 4, 5]);

Run Code 🚀

Code Explanation:

Explain solution here and add any relevant links

Relevant Links

🚨 Advanced Code Solution (Declarative Solution):

function diffArray(arr1, arr2) {
    return arr1
      .filter(el => !arr2.includes(el))
      .concat(
        arr2.filter(el => !arr1.includes(el))
      )
}

diffArray([1, 2, 3, 5], [1, 2, 3, 4, 5]);

Run Code 🚀

Code Explanation:

Explain solution here and add any relevant links

Relevant Links

🏆 Credits:

If you found this page useful, you may say thanks to the contributors by copying and pasting the following line in the main chat:

Thanks @Rafase282 @aganita @abhisekp for your help with Challenge: Diff Two Arrays

📋 NOTES FOR CONTRIBUTIONS:

  • ⚠️ DO NOT add solutions that are similar to any existing solutions. If you think it is similar but better, then try to merge (or replace) the existing similar solution.
  • Add an explanation of your solution.
  • Categorize the solution in one of the following categories -- Basic, Intermediate and Advanced. 🚥
  • Please add your username only if you have added any relevant main contents. (:warning: DO NOT remove any existing usernames)

See 👉 Wiki Challenge Solution Template for reference.

Clone this wiki locally