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Welcome back.

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The methods we're going to talk about when it comes to sets are right here.

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It looks like a lot but they're quite similar so hang in there.

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I have two sets for us are my set which is one through five and then your set which is four through

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10.

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Now let's go one by one and see what these methods do.

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And if you've ever seen Venn diagrams in your school for example two circles that are overlapping each

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other.

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What we're about to do is quite similar to this.

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The first one is difference and sets are very useful when having two sets and comparing them to each

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other.

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So for example in here difference simply says my set dot difference and we give it another set such

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as your set.

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If I print this right here and I click Run I get one two three.

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It's going to find the difference of the first.

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My set with your set so any duplicates between the two which is four and five gets ignored and it only

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shows the difference.

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That is one two three.

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What's different between my set and your set when viewed from my set.

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Well your set doesn't have one two three.

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What about the next one discard again if we do my set DOD discard it says it removes an element from

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a set if it is a member so here we can say discard five and if I do print my set and I click Run I get

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none but if I print here my set and I click Run I get one two three four because we've just discarded

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Five it modifies our set just to keep our working space clean I'm going to comment this out next is

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difference update so I'm going to say my set and then once again let's see what difference update does

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remove all elements of another set from this set.

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So if I do your set here and once again I do print and I click Run I get none because it just modifies

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my set.

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So remember we just have to have our print my set and now this my set is updated with just one two and

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three because we're updating it so that the differences are removed.

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So four and five are removed unlike difference where it just told you the difference without changing

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again if we go back here and simply do my set and I click Run you see that my set here was not modified

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right here but then my set bottom was modified because of difference update right.

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A few more to go.

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Intersection and this one once again my set and in here once again let's see what it does.

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It just has intersection with something else.

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Well let's find out.

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If I do your set here and I do print and I run this it's going to give me four or five because that's

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the intersection the two common things that my set and your set has.

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What about is this joint well.

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If I do my set and then your sect feel like I'm saying those words over and over.

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Hopefully that's not too annoying.

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And then here if let's comment this out we run this.

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I get false is disjoint simply says hey are those two circles overlapping.

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Do they have anything in common if for example my said didn't had four didn't have four and five and

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I click Run I get true because it's disjointed means these sets have nothing in common.

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Awesome.

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Just a few more.

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The next ones we're gonna see is is subset and is superset but actually before we do that let's do union.

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Let's see what this does.

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Union will say my set

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and in here we want to add the other set your set.

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If we print this and click Run I get one two three four five six seven eight nine 10.

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What did that just do.

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Well union just united these sets together but removed any duplicates.

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That's kind of nice.

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And as you can see it created a new set for us.

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It returned to a new set by the way there's actually a shorthand that you can do here in python which

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is the shift and then the key above your enter which is right here the straight line.

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So shift and then the backslash.

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But if you press shift you'll get this that all straight line.

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If you print this will remove the brackets here.

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Let's run again and you see that works as well.

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And by the way this also exists for intersection.

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Again you don't see it that often but with intersection you can do the same thing where you just do

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the end.

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And if you do that

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it gives you the intersection of my set and your set.

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All right I promise you this is going to be short.

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So two other ones is subset and is superset as you can imagine.

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My set if let's say my set only has four and five and I say hey is my set.

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Is that a subset of your set.

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And I print this if I click Run it's true my set is a subset that is it's inside of the circle of your

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set because four and five is inside of it.

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So my set the entirety of my set is inside of this other set which we call a subset.

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On the other hand we also have this idea of superset.

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So if I do instead of is subset is superset I'll get false because while my set is not a superset it

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doesn't encompass your set.

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It's the other way around.

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Your set is a superset of my set

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because your set encompasses everything that my set has which is four and five homeboy.

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That was a lot.

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And you're asking yourself there is no way I'm going to memorize any of that.

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Well good.

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I don't memorize any of this either.

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As a matter of fact I usually go to the Python documentation or just google around and because I know

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sets exist if I ever want to compare let's say two sets I know to just go here and find the tool that

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I want.

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That's the cue of a programmer that I keep mentioning over and over.

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It's not memorization.

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It's the ability to know that there's tools that you can use.

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And being able to Google for them.

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I know it doesn't sound exciting because in movies you see everybody typing super fast encoding everything

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but that's just not real life in real life.

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You just google around find solutions because by now you know what sets are you know what sets can do

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so that you can google for methods that are appropriate to your problem.

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I'll see you in the next one by.