Alright guys, welcome back. Welcome back to MBK world. In this video we're going to be talking about a concept called variables. Basically we need to learn how to store information when we're doing our programs. So how does it work? Okay, so before I go on let me clear my console. There's this nice icon here of the trash can. It can clear my output. And we're going to start over. We're going to talk about variables. So last time we talked about console log, how to print a message to the console. We learned about the concept of a function that takes an argument and as an input and then process does some processing and then output something. And now we need to learn how to store information. Because we I don't know, say you have, for example, you're using, I don't know, you're using Facebook, for example, and they taking many kinds of information, right? They need your name, your birthday, or interest, like many, they want your descriptions, that kind of stuff. So where does all those information go when you see that page? So all those guys are inside a variable, they're stored in a variable. So variable is just some kind of box where you put some stuff and you can retrieve it. You can access it later. Okay, so the way you define a variable in JavaScript. Okay, is the following note I'm using what's called a yes six and beyond JavaScript is an implementation of a language called academic script, which is the standard for the JavaScript language. And I'll be using the ES six, so called academic script 2015. And before that, the language had some constructs. And now they added new constructs to the language. Now the language is much more, you know, much more convenient. And one of those concepts is that they change a little bit how you assign a variable. The old ways that works, but now you can do another way. And this other new way is what I'm going to teach you. Okay, so you declare a variable with a keyword called cost. Okay, cost. So cost. And then you're going to say you have to give the variable a name. It could be anything with certain exceptions for the name convention, but I won't get it to that here. But let's make it simple. Let's say we want to store our names. I'm going to call the variable name. And the value this variable is going to hold, you assign it with the equal operator. Okay. Now you name this case has to be a string, right? Because it's a name. And to that, I am going to write my name. Well, you can write your name, but I'll write my name. Okay, so let's take a look at this. So this is going to be your name. It's a string, remember? String is like a sequence of characters. So on the equal sign, it's an assignment operation. Okay, you're assigning your name to a variable called name this case. Okay, the variable, you choose the name of the variable. When you do programming, and you learn what development you learn that's always good to name your variables to give good name to your variables. So like that, the programmers and developers will understand what's going on right away when they see the name of the variables. So try to name give them a very good name, don't go around naming variables with just one letter or something very cryptic. That's a very bad practice if you're doing development in the real world. All right. So const is a keyword. It's a new thing in ES6, the set before, new version of JavaScript, which is going to be the de facto standard now. Supported by most hopefully is going to be supported by most fully supported by most major browsers very, very soon. Okay. So const, and then the name of the variable equals whatever you want it to be. What's the value? This is called the value of this variable. Okay, now you type enter and then you define the variable. Don't worry about this undefined here. It's the it's actually a return value of this expression. Don't worry about it. Just ignore it for now. Okay. So we define a variable called name that holds the value my name. Okay, so if you want to see what's inside the variable name, since we are in the console, we can just type name, okay, and then enter. And there you go. It's going to say, okay, the value of the variable name is my name. Now, if you want to use this, for example, you want to do a console log, you want to log to the console, the variable, you can use that function we learned console log, right? And then you give an an argument is between the parentheses, you give the function an argument. We're going to give the argument, let's say we just want to console log or name. So you can just type the variable name there. Notice there's no strings. Okay, because this is a variable. And the variable name here has some value. And this value here, my name is going to be substituted here. So it's going to be actually like this. Okay. And then the console log is going to print my name. Okay, so let's see if it really works. Okay, so right here, this line, it print my name. Okay. So that's those are variables. Okay. So let's review, let's review. What we did was define a variable called name, whose value is a string that included your name, my name. We use the keyword const to define this variable. Then you can console log it and just give it the name of the variable and the value of the variable will be substituted here and then be print. Okay. So notice there's no quotes around it because this is not a string. This is a variable. All right. So there's a difference there. Now I want to challenge you. I want you to define a variable. Okay. And this variable is going to be called age. So I want you to define a variable called age, whose value is going to be your age. You don't have to tell me, but you can do it by yourself. Okay. And I'll give a couple of seconds. And as for the value, it could be a string, but what we're going to learn as we're going to learn later, there's also another type of value in JavaScript. And that's a number. Yes. So you can actually type a number and assign it to a variable. And you don't need quotes for that because that's how you differentiate numbers from strings. A string is enclosed by quotes, but a number is not. A number is just numbers by themselves. Okay. So I want you to try that out. Define a variable whose name is age and value is your age as a number. Okay. Type the number, not a string. I'll give you a couple of seconds. So how did it go? So I'm going to hear define a variable, start with keyword const. Then I give the name of the variable I called age. And now we're going to assign a variable, a value to this variable with the assignment operator. And I'm going to just make something up. All right. I'm going to put 35 as a number, not a string. Notice there's no quotes around it. So it's an actual number, another type in JavaScript. So that's it. I can see that there's actually 35 inside that variable. And I want you to console log it. So let's console console log age. See what we get 35. Same as previous line. Okay. So that's it. Hope you liked it. We learned about variables. And at the end, we learned about a new type of value. That's the number. So thank you so much for watching. Please like video and subscribe. And until the next time, bye.