<p dir="auto">Here's a clear definition of set equality. One sees that order is not explicit at all.<br>
<a href="https://proofwiki.org/wiki/Definition:Set_Equality" rel="nofollow">https://proofwiki.org/wiki/Definition:Set_Equality</a><br>
Two sets are equal iff they contain the same elements:<br>
∀x:(x∈A⟺x∈B)⟺A=B<br>
The order of the elements in the sets is immaterial.</p>
<p dir="auto">Is there a way to reopen this topic?<br>
(Edited note: I eliminated the reference to commutativity and associativity of symmetric difference since it is irrelevant to set equality)</p>
<p dir="auto">the youtube video presented in case <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="96729502" data-permission-text="Title is private" data-url="https://github.com/freeCodeCamp/freeCodeCamp/issues/1358" data-hovercard-type="issue" data-hovercard-url="/freeCodeCamp/freeCodeCamp/issues/1358/hovercard" href="https://github.com/freeCodeCamp/freeCodeCamp/issues/1358">#1358</a> does not demonstrate at all that ordering matters.</p>
<p dir="auto">I think the equality of sets is independent of order. {1,2,3} = {3,2,1}<br>
see more here: <a href="http://www.cs.odu.edu/~toida/nerzic/content/set/basics.html" rel="nofollow">http://www.cs.odu.edu/~toida/nerzic/content/set/basics.html</a></p>
<p dir="auto">Please also note that according to the site above that is also true that:<br>
{1, 2, 3} = {3, 2, 1, 1}, that is duplications do NOT make any difference for sets.</p>
<p dir="auto">Challenge <a href="http://freecodecamp.com/challenges/waypoint-sift-through-text-with-regular-expressions" rel="nofollow">http://freecodecamp.com/challenges/waypoint-sift-through-text-with-regular-expressions</a> has an issue.</p>
<p dir="auto">it wants a regular expression <code class="notranslate">/and+/gi</code> but should check for <code class="notranslate">/and/gi</code></p>
<p dir="auto">the plus means it would match <code class="notranslate">andd</code> or <code class="notranslate">anddddddddddddddd</code> instead of just <code class="notranslate">and</code></p>