so in the last video we talked a bit about PHP syntax and today we're going to talk a bit about how to create variables and data types now I do think it's a really good idea that we go inside our editor in this video and just talk a bit about this so we have some practical experience writing vhp code and with that we do need to actually start up our website and I thought why not do that together since that is something we haven't done yet so what you need to make sure you do every single time you want to see your website inside the browser is first of all you need to have your editor open which is step one then you need to make sure you're opening up xampp so you want to open up the software make sure you actually start the Apache and MySQL server then you want to go inside your browser and then you want to go into the URL and type Local Host and when you do that you can see all the websites that you have inside your htdocs folder in my case here I do have two websites you should not have two you should only have one so go ahead and pick the one that we created together in the first episode and then you can see we have our website in front of us here and that's the basic step in order to open up your website when you're running it inside A7 server like xampp so now we can go back inside our index.php and just to kind of talk briefly about the last episode because I know some people are a little bit confused when it came to embedding HTML and PHP together so if I were to go inside I can create a regular HTML paragraph and I can go and create this is a paragraph and just write some text inside this paragraph here now what you can do is you can create the PHP tags so the opening and closing tags so angle bracket question mark PHP then you can say question mark angle bracket so what I could do is echo which we talked about is how to Output things inside the browser I can say this is also a paragraph and we do need to make sure remember that semicolon even though because this is the last statement inside this particular PHP tag here we don't technically need to have this last semicolon but like I said it is best practice to remember to do it every single time because it doesn't hurt anything to do it so let's just go and do it every single time and when you do this you can go back inside your website refresh it and then we can see we have two pieces of text we have this is a paragraph and this is also a paragraph So we have two paragraphs inside our website and just to show something a little bit more complicated you can also go inside existing HTML elements and create PHP so I can go in between here and I can open up my PHP tags and then I can write something additionally in here so it would have to Echo again because we need to make sure to Output whatever we're doing using PHP and I can go ahead and Echo awesome paragraph semicolon save this one go back inside my website and then you can see we've included this awesome paragraph in here and this is just to kind of show that we can mix and match PHP and HTML together in any sort of way that we want by embedding it directly inside the HTML but now this is not what I wanted to talk about in this video here I do actually want to talk about variables and data types because we do have variables and data types which we use constantly when it comes to writing PHP code so this is something we have to memorize so let's go and talk a bit about what exactly a variable is now a variable is when we have a memory location inside our application that stores some sort of data which is a very confusing way for beginners to understand what exactly a variable is because a lot of people don't understand what is memory location and that kind of thing so instead just for practice here let's pretend that a variable is a box and that box has a label so you know when you're moving into a new house you put you know some writing on the box whether it's kitchen utensils or for the the kids room something so you know what's inside the box but then you do also have something inside the Box some actual data so whenever you grab this box by referring to the name of the box then you grab whatever is inside the box as well and that is technically what a variable does so when you reference to a variable you grab the data and it's just a very easy way for us to refer to data and label it so we know exactly what the data is now when it comes to PHP the way you refer to a variable or the way you declare a variable is by creating a dollar sign so if I were to go inside my PHP tags here I can create a dollar sign which means that now we are declaring a variable and then we can call it something so we can come up with a name for this variable that we think makes sense to the data that is inside the variable so in this case here I could say that this is a name so I could say that this is a name and it's going to be equal to some kind of data so now we're initializing this variable by assigning a piece of data to it so in this case here I could say that it is a string which we talked about before called Danny Crossing so now every time I refer to this variable called name I'm going to get a value called Danny Crossing so if I would go below here and just echo which means that we're outputting something inside the browser and I can go ahead and Echo out name or the variable called name so we need to remember the dollar sign here if it were to do this go back inside my website you can see that we're echoing out Danny Crossing so in this sort of way we can create boxes or labels four pieces of data that we can refer to in order to better handle data inside our code so in this case if we create a variable called name and you can call whatever you want but now we do also have naming conventions when it comes to naming these variables here so in this case you can see we call this one variable name but we can also go in and either start it with a letter or a underscore in order to name this variable now the customary thing is to start with a non-capitalized letter and then make sure that any other new words inside this variable name starts with a capitalized letter so if I were to write full name instead then we start out with a non-capitalized F and then a capitalized n for name so whenever you have multiple words inside the variable name then you just make sure the first letter of that second word or third word or fourth word is going to be capitalized and again it's not really a customary thing you have to follow but it's it's the way that people do it so I would recommend doing it the same way so people don't misunderstand what your code does or why you named your variables in this way that other people don't usually do it and just to mention it when it comes to any other letters that isn't the first letter inside the variable name then you can also go ahead and create either underscores or you can create numbers so we can say one but make sure you stick within letters underscores or numbers when it comes to the variable name after the first letter inside the variable name so now let's go ahead and delete what we have here and talk a bit about data types because when it comes to data types inside PHP we have many different data types we're not going to talk about all of them in this video here since some of them are a little bit more complex than others but we will talk about some of the base types that you have inside PSP the first one is going to be what is called scalar types and scalar basically just means that the variable contains one value to it and the first example of that would be we could create a variable that is called something like string and a string we did already talk about what kind of data that is so in this case here we could say uh Daniel so as we know already a string is a piece of text now we do also have numbers so I can go below here and I can create a integer or a int and I'm going to go ahead and name this one a number so we can just write some sort of random number here and this is going to be a value for a integer notice that we're not using double quotes around the number because if I were to do that then all of a sudden this is going to be a string so it's not considered a number inside the PHP language anymore it is actually considered to be a piece of text just like a string up here and you can actually tell by the color that it actually changed it to text now we do also have something called a float which is something that we see happen a lot in many other programming languages which is essentially when you have a number that has decimal points so if you were to write something like 2.5678 then this is going to be considered a float because it has decimal points and then we do also have one more scalar type which is called a Boolean now I'm just going to write bull even though it is spelled Boolean we're just gonna write bull for short and this one is going to be a true or false statement so essentially is something true or is it false and the values for that is going to be false or it is going to be true now it is also important to mention here that if you were to have numbers in here and you were to run this as a Boolean then one is also going to return as true and 0 is going to return as false but in most cases we do just use true or false when it comes to this type of data here and just because I talked about it in the last video let's go and create a comment for this section here so know exactly what this is so we're going to create a one line comment and I'm going to call this one scalar types now the next one we have is actually one that we're not going to do too much with here in the beginning but we do also have a array type so we can actually go and create a comment and call this one array type and essentially a array is when we have a variable that has multiple pieces of data inside of it so just like scalar types which means contains one value in the case of an array we have multiple values inside one variable so could for example create a variable called array and I can name this one equal to multiple pieces of data now we do have two different ways you can create an array one is by writing array parentheses semicolon and then you can add multiple pieces of data in here which could for example be a bunch of strings so I can go in here and say we have one string which is called Daniel and then I can create a comma and then add a second string which could be Bella and then I can add a third piece of data and I can just keep piling data on inside this array here so we can say Theta which is also a string and then we could of course rename the array to something like names if that makes a little bit more sense to what exactly this piece of data has inside of it but essentially this is going to be a bunch of data inside one variable and just to mention it since I did mention there was another way to do this instead of creating array parentheses you can also do a square bracket and then close it off using a square bracket as well just like this now if you just started following this course here you should have a newer version of PHP but if you do run PHP 5.4 or lower then these square brackets are not going to work when it comes to writing a PHP code so if you run a older version of PHP then you do have to do it the way by creating this array around it but just like I said if you're a little bit confused about why we use arrays inside our code you may have questions about it don't worry too much about it because you will get to talk more about arrays in the future for now like I said you're only going to have to worry about these different scalar types here I do want to mention one more data type though even though it's not one you should concern yourself with here at the beginning since this is something that's a little bit further ahead in this course here but we do also have something called an object type so we can say object type and an object type is essentially just when we have a object that is equal to a variable objects is something we create based on classes which is something we again are not talking about right now but when we do instantiate a class we do actually create a variable that is equal to an object based off of that class so I could for example say that we have a variable called object and then we set it equal to a new object which is going to be the name of the new object so we could for example say car parentheses and semicolon and this would instantiate a new car object which of course right now can't find because we don't have it but once we do have a class called card that we can instantiate then this is not going to throw an error message but like I said we're not really going to worry too much about arrays and Optics right now this early on in this course here so don't worry if you get confused about them because that is perfectly normal even though we're not really supposed to talk about raising Optics yet I still thought it was important to just kind of like mention them because it is something that is very used inside PHP so knowing about them so you have kind of like a a little bell inside your head when we talk about objects in a future episode and you think to yourself oh wait I heard about that at some point inside this course here and then you might go back to this lesson here and think oh yeah we talked about objects in that early lesson oh now we get to talk about what exactly it is so don't worry too much about it right now it is something that you just need to have kind of like in the back of your head it's not important right now the only thing you need to worry about right now is that we have these scalar types and when we actually create the variable we declare the variable and then we initialize it by assigning a value to it the reason I mention that is because it is possible to go down and create a variable and let's just go and call it names and not assign anything to it and when you do this depending on the context of when you use this variable it is going to default to a certain value type so if you were to use this one in a string context then it will just go and say oh okay so this is supposed to be a string automatically and then it's just going to assign a empty string to it and it will actually do something that looks like this so we just have an empty string that doesn't have any sort of value inside of it and this is what it's going to default to and the same thing goes for integers floats and booleans and arrays and objects they all default to something so in this case if I were to go ahead let's just go and use these up here so as a default a string defaults to nothing so just an empty string with double quote by the way an integer is going to default to zero and the same thing goes for floats they also default to zero and when it comes to booleans they default to false and just to mention it here when it comes to an array so if we were to create a array because we did talk about them in this video so we do also need to just kind of mention this it is going to default to a empty pair of square brackets and when it comes to an object they default to null which means nothing null is not a concept that we're going to talk about right now but it just basically means nothing however when it comes to declaring a variable you should always initialize it the reason I say this is because sometimes when we do create variables we don't know what should be inside the variable just quite yet and in those cases we just declare a variable but we wait with assigning any sort of value to it and when those moments happen you should not do it this way because you do risk getting error messages inside your code so make sure that you always assign something to it by initializing the variable so with strings you put empty double quotes with a integer you put a zero the same thing with floats if you put a Boolean always set it to false arrays are just going to have these square brackets here and objects are just going to be null so these are going to be the default values you should always put inside a variable if you don't know what kind of data you should put inside of it just quite yet otherwise your interpreter is just going to throw you a warning in a lot of cases so so just go ahead and make that into a habit and here at the end before we end up the episode I just want to say that it is perfectly normal to be completely overwhelmed with all this information here because this is a lot of information I'm dumping on people especially if this is your first programmer language this is going to be completely new and this is going to be a lot of information I just want to say that it's perfectly normal to be overwhelmed and in the future we will get to do many more practical examples so we do actually use variables for something and we use many different data types and it is something that is just going to be a bit more natural when you actually start seeing how these are used in Practical examples and when you get that little oh okay Epiphany moment where okay so this is how we use these different things we've learned up until now then at that point you will remember things a lot easier okay so don't be worried about if you can't memorize all these things because no one expects you to memorize all these things in one sitting it is something that sticks with you as you start practicing PHP along the way just to give a short example here at the end just so people know exactly how we can use variables inside our code if I were to go back inside my body sex here and at the very top I'm going to go ahead and declare a variable called name I'm going to set this one equal to a string called Danny Crossing and what we can do here is we can go below and create a paragraph inside HTML then I can just go and say hi my name is and then we're going to open up PHP tags close it off again comma and I'm learning PHP then what you're going to do is you're going to go up and grab your variable name and you're going to go inside your PHP tags and you're going to Echo out your variable name semicolon and when you do this and go inside the browser and refresh it you can see that now it says hi my name is Danny Crossing and I'm learning PHP so in this sort of way we can take data or variables and we can use them inside our code or inside our HTML if you want to do that to Output data in this sort of sense like this is a very basic example but just to kind of show that we can use variables to reference to data that we assign to variables and just to mention one more thing because something we can also do is we can go down and say I want to create a new variable and I just go ahead and call this one something like test just to give it some kind of name I can assign equal to name so in this case here we have a variable that is assigned equal to a variable and it would take this name and copy it down instead of the echo you'll now notice that we still do get hi my name is Danny Crossing and I'm learning PHP and that is because this this first variable here has a piece of data assigned to it and then the second variable down here has that same variable which has data inside of it assigned to itself so we can also assign variables equal to variables in this sort of way here and with that we now know a lot about variables so I hope you enjoyed this episode here and I'll see you in the next video [Music] [Music] thank you