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Hello and welcome back to another Alphatech Academy video.
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My name is Vlad.
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And in this video, we're going to talk about logical operators.
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So we use the logical operators in our day to day life without paying much attention to it.
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For example, if we can take a slice of bread and some spread, then we can make a delicious sandwich.
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Another example, we can say that if it's raining outside or worry it's cold today, then you should
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take your jacket with you.
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So if we take a look at the first example, we can see that it has basically two, let's call it this
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way, to sub conditions.
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The first one is if we take a slice of bread.
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This is the first condition.
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And the second one is if we take some spread and if we want to use some formality here, there are these
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two sub conditions are called operands.
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So there is the first one and the second one.
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And these two sub conditions.
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These two operands, basically what they do is they form by using a logical and operator.
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They form a new condition.
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And this combined condition may also be true or false based on the status on the result of these SAB
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condition, based on the result of these two operands.
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And they're the and logical operator that we use between them.
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And now the question that remains is how can we decide if the result will be true or false?
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And for that, we can use a truth.
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They will.
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That will help us with the decision.
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And this truth table is very straightforward.
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Once you understand it.
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So let's suppose that we have this little nice table with a couple of columns and a couple of rows.
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And we will say that the first column will represent the status or the result of the first operand over
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the first subcommission, which we took, for example, that it stands for.
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If we take a slice of bread.
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OK.
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So that's the first operand.
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And the second column in this truth table will represent the status of the second sub condition of the
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second operand, which stands for.
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If we take a spread.
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So the first condition is if we take a bread, OK.
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And the second one, if we take a spread and each of these operands may be either a true or false.
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And basically there is a total of four optional combinations between them.
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Either both of them are true or maybe one of them is true and the second one is false or both of them
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are false.
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Let's eat.
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Right.
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Either both of them are true or the first one is true.
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The second one is false or otherwise.
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The first one is false and the second one is true, or both of them are false.
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There are no other combinations that you can do with these two sub conditions.
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All right.
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So these were just the operands of our overall expression.
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Now, let's see what would be the result of using an and logical operator on both of them.
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So if you have a slice of bread and you have a spread, then it means you can make a sandwich.
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So it means that if both of these sub conditions are true, then the overall resolved is true.
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You can make a sandwich.
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But if you don't have at least one of them either, it's a slice of bread, worries bread.
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Then you can not make a sandwich.
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You will have just one of the ingredients.
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But it will be it won't be sufficient to make your favorite sandwich.
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Right.
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So the overall result in this case is that both of them are going to be false.
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And lastly, if there is no bread and no spread, then it is obvious that there is no sandwich.
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So the result is definitely going to be false.
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Now, what we've done is we've simply created a truth table for the for the and logical operator.
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So whenever you're going to work with a and and logical operator and you have a couple of sub conditions,
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you can use these Troost, they will to help you understand what will be the result, the overall result
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of the condition itself.
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So once again, based on the status of the given operands that you can see in these columns, if you
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use the logical and operator between the two, then the result is going to be exactly as you can see
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on the last column, on the right one.
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So I hope that's clear to you guys.
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And you understand everything we've just discussed.
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And just to make sure that you do.
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I'm going to give you another.
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Example using the and logical operator.
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So let's say that you want to ask for some money from I don't know whom maybe your parents, your friends,
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your colleagues or anyone else.
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And since you know they care for you, you know they will help you, but they will help you only if
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you have less than, let's say, 50 bucks in your wallet.
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And also, they will not just give you the money based on that condition alone.
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They also want you to succeed in school.
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So there is a second condition which says that you have to get a grade higher than 90 on your programming
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the exam.
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And if both of these conditions are satisfied, then you will preened the following message.
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Give me some money, please.
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I've earned it with a high grade and nothing in my pocket.
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So pretty funny example.
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But let's try to look more into it.
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So this message will be printed only if both of these conditions happen to be true.
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So we've won.
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We have less than 50 bucks in a wallet.
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And two, if we've got a grade higher than 90 on our last exam, only then we would preened this message,
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asking for some money in a reward.
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So I hope the example is clear to you guys and you understand the logic behind using IM and logical
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operator.
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And now what I want to do is to talk about the second example, a sentence we probably mentioned at
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the beginning of the topic, I guess.
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And it goes like this if it's raining outside or it's cold today.
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Take your jacket with you.
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Let's try to construct to the or a logical operator a table ourselves, shall we?
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So first of all, we can say that the first operand, the first sub condition relates to if it's raining
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outside and the second one relates to if it's cold today.
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And if both of them are true, we can say that we definitely should take the jacket.
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Right.
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If both of them are true, if it's called and if it's raining, then we should take our A jacket with
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us.
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We know that if it's raining outside, then it doesn't matter if it's called or not, then we should
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also take a jacket with us.
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Similarly, we if we know that it's cold outside, then it doesn't matter if it's raining because it's
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cold, it's outside.
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So meaning that for both of these cases, if one condition, at least one condition happens to be true,
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the result is also going to be true.
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So we need the jacket with us.
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And lastly, only if it's not raining and it's not cold today, only then you don't have to take your
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jacket with you.
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Meaning the result in this case will be false.
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It's not cold.
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There is no rain and there is no reason to take the jacket with us.
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So that's basically how you create a truth.
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They will for the or logical operator and just go over it once again.
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If either of the conditions, either of the operands happened to be true, then the overall result will
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be true.
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And just remember this nice example of the called Arean.
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If it's raining example that we use right now and shoot you or shoot, should you not take your jacket
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with you?
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And that's good guy sound.
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Now we know how the logical or operator and the logical and operator, how both of them work.
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And now we can simply summarize what we've learned so far.
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So we may have a couple of operands, a couple of these sub conditions.
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And also we may have some logical operators that are applied on these operands.
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And the final result of all of these, let's say, process is decided to be either true or false.
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It doesn't matter if it's complicated and it doesn't matter how much operands or logical operators you
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may use.
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The final result may only be either a true or false.
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It also it all comes to these same programming.
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OK, eventually that's all we have.
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Either a true or false sense, zero or one.
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And that's how programming work.
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So I hope this structure, their usage of these truth tables is clear to you guys.
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And one last thing that I want to talk about in these video is the last logical operator, which is
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called the not logical operator.
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And the it's the easiest one, actually.
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It simply takes some expression and whatever its final result to you, the way it's true or false.
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These not.
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Rader will return the inverse value.
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So we feel is applied on a value that happened to be true.
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Then the final result would be false.
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And vice versa.
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So we'd simply negates the result.
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And once again, if this not operator is applied on some expression, which is true, then the final
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result is going to be false.
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And if it is applied on an expression which happens to be false, then the final result is going to
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be true.
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So thank you guys for watching your on Alphatech Academy programming course.
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My name is Vlad.
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And now we can move on to practice logical operators in our programming language.
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I'll see you there.
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