‫Welcome back.
‫The methods we're going to talk about when it comes to sets are right here.
‫It looks like a lot, but they're quite similar.
‫So hang in there.
‫I have two sets for us are my set, which is one through five.
‫And then your set, which is four through ten.
‫Now let's go one by one and see what these methods do.
‫And if you've ever seen Venn diagrams in your school, for example, two circles that are overlapping
‫each other, what we're about to do is quite similar to this.
‫The first one is difference and sets are very useful when having two sets and comparing them to each
‫other.
‫So for example, in here difference simply says my set dot difference and we give it another set such
‫as your set.
‫If I print this right here and I click Run.
‫I get one, two, three.
‫It's going to find the difference of the first my set with your set.
‫So any duplicates between the two which is four and five?
‫Gets ignored and it only shows the difference.
‫That is one, two, three.
‫What's different between my set and your set when viewed from my set?
‫Well, your set doesn't have 1 to 3.
‫What about the next one?
‫Discard.
‫Again, if we do my set.
‫DOD discard.
‫It says it removes an element from 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 none.
‫But if I print here my set and I click Run.
‫I get one, two, three, four because we've just discarded five.
‫It modifies our set just to keep our working space clean.
‫I'm going to comment this out.
‫Next is difference.
‫Update.
‫So I'm going to say my set.
‫And then once again, let's see what difference update does.
‫Remove all elements of another set from this set.
‫So if I do your set here.
‫And once again, I do print and I click run.
‫I get none because it just modifies my set.
‫So remember, we just have to have our print.
‫My set.
‫And now this.
‫My set is updated with just one, two and three because we're updating it so that the differences are
‫removed.
‫So four and five are removed, unlike difference where it just told you the difference without changing
‫again, if we go back here and simply do my set.
‫And I click Run.
‫You see that?
‫My set here was not modified right here.
‫But then my set bottom was modified because of difference.
‫Update.
‫All right.
‫A few more to go.
‫Intersection.
‫And this one once again, my set.
‫And in here once again, let's see what it does.
‫It just has intersection with something else.
‫Well, let's find out 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 the intersection, the two common things that my set
‫and your set has.
‫What about this this joint?
‫Well, if I do my set.
‫And then your set.
‫I feel like I'm saying those words over and over.
‫Hopefully that's not too annoying.
‫And then here, if let's comment this out, we run this.
‫I get false is disjoint simply says, Hey, are those two circles overlapping?
‫Do they have anything in common?
‫If, for example, my set didn't had four, didn't have four and five and I click run.
‫I get true because it's disjointed.
‫It means these sets have nothing in common.
‫Awesome.
‫Just a few more.
‫The next ones we're going to see is is subset and is superset.
‫But actually, before we do that, let's do union.
‫Let's see what this does.
‫Union.
‫Well her say my set.
‫And in here we want to add the other set.
‫Your set.
‫If we print this.
‫And Click Run.
‫I get one, two, three, four, five, six, seven, eight, nine, ten.
‫What did that just do?
‫Well, Union just united these sets together, but removed any duplicates?
‫That's kind of nice.
‫And as you can see, it created a new set for us.
‫It returned a new set.
‫By the way, there's actually a shorthand that you can do here in Python, which is the shift and then
‫the key above your enter, which is right here, this straight line.
‫So shift and then the backslash.
‫But if you press shift, you'll get this little straight line if you print this.
‫Well, remove the brackets here.
‫Let's run again.
‫And you see that works as well.
‫And by the way, this also exists for intersection.
‫Again, you don't see it that often, but with intersection, you can do the same thing where you just
‫do the.
‫And.
‫And if you do that.
‫It gives you the intersection of my set and your set.
‫All right.
‫I promise you, this is going to be short.
‫So two other ones is subset and is superset.
‫As you can imagine, my set if let's say my set only has four and five.
‫And I say, Hey, it's my set.
‫Is that a subset of your set?
‫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 set because four and five is inside of
‫it.
‫So my set, the entirety of my set is inside of this other set, which we call a subset.
‫On the other hand.
‫We also have this idea of superset.
‫So if I do instead of is.
‫Subset is.
‫Superset.
‫I'll get false because, well, my set is not a superset.
‫It doesn't encompass your set.
‫It's the other way around.
‫Your set is a superset of my set.
‫Because your set encompasses everything that my set has, which is four and five.
‫Oh, boy, that was a lot.
‫And you're asking yourself, there is no way I'm going to memorize any of that.
‫Well, good.
‫I don't memorize any of this either.
‫As a matter of fact, I usually go to the Python documentation or just Google around and because I know
‫sets exist.
‫If I ever want to compare, let's say two sets, I know to just go here and find the tool that I want.
‫That's the key of a programmer that I keep mentioning over and over.
‫It's not memorization.
‫It's the ability to know that there's tools that you can use and being able to Google for them.
‫I know it doesn't sound exciting because in movies you see everybody typing super fast and coding everything,
‫but that's just not real life.
‫In real life, you just Google around, find solutions because by now you know what sets are, you know
‫what sets can do so that you can Google for methods that are appropriate to your problem.
‫I'll see you in the next one.
‫Bye bye.