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Welcome back everyone.

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It's time to begin discussing the very basics of control flow.

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We're going to start by talking about comparison and logical operators comparison operators basically

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allow us to compare two different objects.

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So for numbers we can do things like compare if one is less than two or if two is greater than one.

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The other object types we can also just straight up compare or do the same thing.

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We can do this with an equals equal sign or we can compare if they're not the same thing with an exclamation

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mark will sign.

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So we're going to see some examples of those and we'll also expand this to do things like greater than

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or equal to or less than or equal to.

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Now for logical operators those are going to allow us to combine multiple comparison operators essentially

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chaining comparison operations.

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Let's get a better idea of all this by jumping over to the Adam text editor.

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OK here I am I thought py file.

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I want to start a couple of basic examples such as greater than or equal to.

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So we're going to say one greater than two.

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And I'm going to print the results of this so we can see it at our command line and then we'll kind

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of play around with this.

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So these are basic comparisons these comparison operators basically allowing us to compare two numbers

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together is one greater than two.

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And that's going to bring back the boolean false.

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So far so good.

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If I were to change this to something that would be true like is three greater than 2.

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I run that again that we get.

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True.

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So the basic comparison you can make are greater then or less then and then you can also do greater

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than or equal to or less than or equal to.

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So for example is three Lessner equal to 2.

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Well that's going to do false.

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If we run this.

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But let's change this to three.

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So it's three Lessner equal to three.

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Well that's true x 3 is equal to 3.

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So when you run that back you get true.

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So those are the main person operators for numbers really useful ones are when you compare for equality.

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So for example if I just wanted to compare for equality I used to equal signs.

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So two equal science performance comparison one equal signs here will actually give you an error because

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it's going to try to do a variable assignment.

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So remember for comparisons used to equal signs.

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So we're going to say three is equal to three.

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And when you read that you get back.

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True.

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And if you want to check Nonni quality you can say is three not equal to three which would give us false

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because 3 is equal to 3.

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So on a run that I get back false.

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Keep in mind this sort of equality doesn't just have to be for numbers.

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So for example let's say we have some sort of username and the username provided is adamant.

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And then we have our own check inside the system so I'll say our check is equal to admin as well.

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And notice I've capitalized am both.

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Well I could do is saying Prince is username equal to my check and that's something we're going to be

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doing a lot through our code checking for equality.

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And this ends up becoming true.

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So what's really useful about comparison operations is then you can check for things to be true or false

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and then run code based off those decisions.

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For example if a user name was admin and it equaled our check maybe we give this person more permissions

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for a web site that sort of thing.

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OK so those are comparison operators.

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But often you'll want to have multiple comparisons done at the same time.

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So for that you can use logical operators like and or or.

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So let's show you an example of that.

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Let's start with a simple comment.

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So I'm sort of a very simple example of is one equal to 1.

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So as you would expect when I run this I get back.

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True.

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Let's imagine I want to do another comparison maybe is one equal to 1 and is 2 less than three.

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So now when I run this I get back.

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True because one is equal to 1 and 2 is less than three.

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But let's make one of these.

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Not the case because.

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And it's going to need to check for all conditions to be true.

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So now when you run this you're going to get back false because one is not equal to two.

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So and requires that all conditions be true.

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If I changed this to or that requires at least one of these conditions to be true.

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So now when you run this you're going to get back true because even though the first one is false the

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second one happens to be true.

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So those are the AND and OR.

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And you can change these as high as you want so you can say is one to two or two equals a three or is

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four equal to four.

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And so on.

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So you can check those conditions for you.

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And often people like to wrap these separate conditions into parentheses just so it's easier to read.

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So you can see that as well there.

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So you kind of get an idea of each condition being checked.

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It's kind of up to you in the situation whether you want to use print sees it may make your code more

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readable so just keep that in mind.

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OK.

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So let's go into this festering example let's add in some permission variable and we're going to set

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this permission variable to a boolean false.

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So it's already a boolean.

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So I'm going to print is user name equal to check and permission.

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So no what's happening here.

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For permission I'm not actually providing some sort of comparison.

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I'm just providing a straight up boolean because remember comparison operators they always resolve to

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a boolean itself.

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So really and that or they're just looking for booleans does have to be a comparison operation.

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So when you run this think about what I should get adamant is equal to admen.

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But right now permission is false.

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So when I run this I get back false because currently there is no permission there.

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However let's change permission to be true.

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Save it and run it and then you get back.

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True.

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So this sort of clever choosing of your variable names allows your code to be super readable.

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So for instance I can say something like logged in is equal to true.

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And permission is equal to true.

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And later on in my code I could just read type and log in and permission.

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And it can even make it more readable by making this variable has permission and I'll change this to

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has permission.

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And now this basically reads like an English sentence.

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I'm asking Prince are they logged in and has permission.

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And in this case they are both true.

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So the result when I print this is true.

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So keep in mind these logical operators they don't necessarily need actual comparison operators they're

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just looking for booleans which at the end of the day is what a comparison operation such as username

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equals equals check is returning back to you.

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OK so that's the very basics of comparison operators and logical operators.

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Coming up next we're going to continue our discussion of control flow by talking about if elif and else

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statements.

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We'll see if they're.