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Challenge 117: Symmetric Difference

curriculum/challenges/english/blocks/daily-coding-challenges-javascript/69162d64f96574d9bb629f02.md

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--description--

Given two arrays, return a new array containing the symmetric difference of them.

  • The symmetric difference between two sets is the set of values that appear in either set, but not both.
  • Return the values in the order they first appear in the input arrays.

--hints--

difference([1, 2, 3], [3, 4, 5]) should return [1, 2, 4, 5].

js
assert.deepEqual(difference([1, 2, 3], [3, 4, 5]), [1, 2, 4, 5]);

difference(["a", "b"], ["c", "b"]) should return ["a", "c"].

js
assert.deepEqual(difference(["a", "b"], ["c", "b"]), ["a", "c"]);

difference([1, "a", 2], [2, "b", "a"]) should return [1, "b"].

js
assert.deepEqual(difference([1, "a", 2], [2, "b", "a"]), [1, "b"]);

difference([1, 3, 5, 7, 9], [1, 2, 3, 4, 5, 6, 7, 8, 9]) should return [2, 4, 6, 8].

js
assert.deepEqual(difference([1, 3, 5, 7, 9], [1, 2, 3, 4, 5, 6, 7, 8, 9]), [2, 4, 6, 8]);

--seed--

--seed-contents--

js
function difference(arr1, arr2) {

  return arr1;
}

--solutions--

js
function difference(arr1, arr2) {
  const diff = [];

  for (const v of arr1) {

    if (!diff.includes(v) && !arr2.includes(v)) diff.push(v)
  }
  
  for (const v of arr2) {
    if (!diff.includes(v) && !arr1.includes(v)) diff.push(v)
  }

  return diff;
}