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Welcome back.

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So up until now, we've learned about integers, floats, strings and Boolean values.

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So let's try and tie some of those things together.

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Let's imagine your Facebook.

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How do you think Facebook works underneath the hood when it comes to your profile?

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Well, they would have, let's say, a variable called name.

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And this will have your name.

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And then they'll probably have a variable with your age.

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Let's say 50.

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I'm not actually 50, but I'm pretending to be for this case, just so I sound wiser.

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And then, let's say relationship status.

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So again, we also have relationship status on Facebook.

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And for now, let's say single.

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So that's my Facebook profile right there.

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Now, if we wanted to perhaps change that, let's say my relationship status all of a sudden goes from

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single to it's complicated.

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Well, that's an easy fix.

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We would just do relationship status equals to.

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It's complicated.

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And remember, because of the single quote, we'll have to do backslash.

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It's.

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Complicated.

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And now if I print my relationship status.

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You'll see that it's been updated to.

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It's complicated.

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I am no longer single.

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Hooray!

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But this is pretty simple.

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Let's do something more complicated.

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And this is going to be a fun exercise.

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Let's create a program that guesses your age.

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Let's use the input method that we've seen before.

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Remember, the input method allows us to type something.

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In here and receive it as input so we can assign that to a variable.

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So let's say this variable is going to be birth year and that's going to equal the input that's going

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to ask.

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When or what year were you?

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Born.

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Now from here, I want you to pause the video and try to solve this yourself.

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How can you make it so that at the end of this program you're going to get asked, what year were you

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born?

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You're going to type in your ear, and then it's going to print out your age is whatever the age is.

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So pause the video.

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Try and solve this on your own.

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Mind you, there is a bit of a trick in here.

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So if you get stuck, try to Google around and figure out what the issue may be.

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Again, part of being a programmer is trying to solve these problems that you don't know the answers

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to.

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All right.

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Let me show you my solution.

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We have our birth year here that we're going to store in a variable.

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And now we're going to calculate the H, I'm going to say H equals well, it's going to equal the current

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year, let's say 2019 and then 2019 here is going to get subtracted from whatever the birth year that

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you enter.

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So let's enter that.

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And then we're simply going to say, print your age is.

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And we want to use an F string here.

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So I'm going to add an F here.

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And then simply say.

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Age.

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If I run this.

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I get?

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What year were you born?

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I was born in 1986.

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Hmm.

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We get an error, and if you try this yourself, you may have encountered this error.

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We get something called a type error and there's lots of errors that you can get in Python.

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Again, we have a section on error, so don't stress too much about it.

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But if you read here, it says unsupported operand type SW four minus int and string.

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Hmm.

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Let's try and debug this.

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It looks like we're using minus on an integer and a string.

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So let me print out here the type of birth year.

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If I run this and let's enter 1986, I get class string and this is a little gotcha because what input

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does is it asks you for an input, but that input that I wrote 1986 well that actually gets converted

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to a string and assigned to birth year.

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So what that means is that we're trying to subtract.

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A number or a string from a number.

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So how do we solve this issue?

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Well, you'd have to turn this into an integer.

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And this is something that we saw previously.

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What we need to do is to convert this into an integer with using the int function.

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So let's try that.

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If I remove this and click run.

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I'll say 1986.

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And look at that your age is 33.

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We've created a program that is able to tell your age based on the year that you were born.

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Now, this may have been tricky to you, but it teaches an important concept in programming.

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That is, sometimes you're storing data into different data types, and sometimes you need those different

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data types to interact together.

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So you'll see a lot of problems where you have to convert a data type.

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And this is a very common one where you take an input that's a string and then you convert it to something

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like an integer.

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So you can perform a mathematical operation.

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And that's why, if you remember, we gave you a list of all our data types in Python, the fundamental

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data types, and all of them were blue because well, each one of these are actions are functions that

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we can use.

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For example, I converted the birth year into integer, but I could have also converted this to a float,

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for example.

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And if I run this, it would still work.

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Because Python knows that well, we can use integers and floats in mathematical operation, but you

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can see here that it's converted into a float.

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Now, if we convert this into a boolean.

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And I click Run.

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Your age is 2018.

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That's really confusing, right?

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Well, that's because this gets turned into true.

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And underneath the hood, python does something weird where a true value is converted to one.

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Because Boolean remember it's one or zero.

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True or false.

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All right.

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Hopefully this didn't confuse you too much.

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It's something that will encounter throughout the course.

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So don't worry.

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We'll get more and more practice.

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However, I hope you get to practice this a little bit to really understand what's going on, because

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although this is a couple of lines of code, the principles that we use here, we're going to use throughout

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bigger and bigger code bases.

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So I guess I'll see you in the next one.

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Bye bye.