Practical PHP: Master the Basics and Code Dynamic Websites

Lecture 6: Your First PHP Web Page

In this lecture we're going to be learning how to set up a virtual server to run your very first PHP web page. How exciting!

Lecture 7: PHP Syntax

In this lecture we're going to be learning a little bit about the basic syntax of PHP programming. It's a quick lecture, but very necessary in order to get started on the right foot.

Lecture 8: PHP Variables

Think of a variable as a bucket. Literally, a bucket. That bucket can hold stuff in it — like food, or dirt. In PHP, variables are buckets, but instead of holding food or dirt, they hold information — like numbers, text, images, or logic! All you need to know at this point is that variables are buckets that store information for later use. We'll get to how we actually use the variables in an upcoming lecture.

The basic syntax of a variable is a dollar sign ($) directly followed by a variable name (using text, with no spaces), then an equal sign, followed by the contents of the variable, ending with a semi-colon. Ex: $variable_name = 'my first variable';

There are 4 basic variable types, and each type of variable (or "bucket") is meant to hold specific information. Watch the lecture or download the PDF to learn what the 4 basic variable types are.

Lecture 9: More Variables

In this lecture, we cover a couple more examples of the basic usage of PHP variables.

Lecture 10: Defining Constants

A constant is similar to a variable in the sense that you can store information in a keyword that can be used throughout your web page. However, the value of a constant cannot be changed, unlike a variable. It's literally "constant".

It's also worth noting that constants are case-sensitive and are written in ALL CAPS by convention. Here's how you define a constant in PHP:

To display a constant on your page, you can echo it using PHP, like this:

<?php echoTITLE; ?>

Lecture 11: Get Your Hands Dirty!

In this lecture we put in to practice everything we've learned so far:

• PHP Variables
• PHP Constants

Simple and straightforward, you will be able to see the benefits of using variables and constants right away!

Lecture 12: Arrays

Sometimes you'll want to store more than one value within your variables. With an array, you can do just that! Arrays allow you to store multiple values within a variable.

For example, I think moustaches are neat. There are many kinds of moustaches! Using individual variables, I can store each moustache in their own, like so:

$moustache1 = "Handlebar";

$moustache2 = "Salvador Dali";

$moustache3 = "Fu Manchu";

But, I'd like to keep things neat n' tidy and have all my moustaches in a single variable. So I'll use an array, like so:

$moustaches= array("Handlebar", "Salvador Dali", "Fu Manchu");

Each value is automatically assigned a "key" in the array, so we can grab a specific value when we need it. We'll touch on keys later, but by default, each value has a numeric key assigned to it.

So for example, "Handlebar" is 1, "Salvador Dali" is 2, and "Fu Manchu" is 3. Here's the catch though — the numbers start at 0, not 1. So, "Handlebar" is actually 0, etc.

If we want to grab a value out of an array and display it on our web page, we just reference the array and the key associated with the value we want to display, like so:

<?php

echo $moustaches[0]; // this will display "Handlebar"

echo $moustaches[1]; // this will display "Salvador Dali"

echo $moustaches[2]; // this will display "Fu Manchu"

?>

Arrays are pretty powerful, and there's a lot more to them. So stay tuned!

Lecture 13: Associative Arrays

Remember how PHP automatically assigns a number to each item in an array? Well, using Associative Arrays you can give a custom name to the key, rather than using a number. It looks like this:

$handlebar = array(

name => "Handlebar",

creep_factor => "High",

avg_growth_days => 14

);

Now, let's say I wanted to display specific information from the array. I would do so by simply referring to a custom key in the array, like this:

<?php echo$handlebar[creep_factor]; ?>

Lecture 14: Multi-Dimensional Arrays

This is where we start getting crazy! We can harness the true potential of arrays by using multi-dimensional arrays — which is simply an array that is comprised of multiple arrays!

$moustaches = array (

array (

"name" => "Handlebar",

"creep_factor" => "High",

"avg_growth_days" => 14

),

array (

"name" => "Salvador Dali",

"creep_factor" => "Extreme",

"avg_growth_days" => 62

),

array (

"name" => "Fu Manchu",

"creep_factor" => "Very High",

"avg_growth_days" => 58

)

);

You're probably wondering how the heck we display this info on the screen! Well, we first have to reference the parent array $moustaches, then the numerical value of the child array (Handlebar is [0], Salvador Dali [1], etc), and finally the custom key of the information we want to display (name, creep_factor, etc). It looks like this:

<?php echo$moustaches[2][name]; ?>

The above code will display Fu Manchu.

- - -

Important update regarding the "keys" in your arrays:

After recording the last two lectures, and publishing my course, it came to my attention that I made a little mistake!

I have a bad habit of not wrapping my keys in my associative & multidimensional arrays in quotations, or "strings".

For example

The incorrect way of coding associative arrays:

$handlebar = array(
		name => "Handlebar",
		creep_factor => "High",
		avg_growth_days => 14
	);

The correct way of coding associative arrays:

$handlebar = array(
		"name" => "Handlebar",
		"creep_factor" => "High",
		"avg_growth_days" => 14
	);

Some servers, like MAMP, might not report the error, and just assume the keys are wrapped in strings. Some servers are not as forgiving as MAMP on a Mac, very obviously letting you know you made an error.

It's very important that your key names in your associative and multi-dimensional arrays are wrapped in quotation marks, single or double.

No worries though! The course files have been updated (as of July 25, 2014), and you probably already have the updated files. For your reference, the exact folders that have been updated are:

• 07_AssociativeArrays
• 08_MultiDimensionalArrays
• 09_GetYourHandsDirty
• 26_Final/Instructor

Thank you very much to everyone who pointed this out!

Cheers,

Brad

Lecture 15: Get Your Hands Dirty

In this lecture, we put together what we've learned so far about PHP Variables, Constants and Arrays!

Lecture 16: If Statements

The point of coding in PHP is to make your website dynamic—or smart—so that it can make logical decisions. What I mean by this is your website can make decisions on what to do next based on user input, user conditions, or parameters you've set yourself. Here are some examples:

• When a user logs into their account, they must type both their username and password. What if their password is wrong? What if they didn't type a valid email address? What if they forgot to type their email address altogether? PHP can handle what to do in these situations using If, Else, and Elseif statements.
• What if a customer tries to buy a product online, but that product is sold out? PHP can let the user know the product is sold out because you can program it to calculate how many items of that product are remaining.
• What if a user uploads an image that is too large? PHP can compare the uploaded image with your parameters and tell the user to upload a smaller image size if it exceeds the limit.
• ...and so much more!

Let's start with the If Statement. It works something like this:

Okay, that was a little vague. Let's expand on that a bit:

If expression is TRUE, then do something

If expression is FALSE, then don't do anything

What's an Expression?

You're probably wondering what an "expression" is. Here's how PHP.net explains what an expression is:

Expressions are the most important building stones of PHP. In PHP, almost anything you write is an expression. The simplest yet most accurate way to define an expression is "anything that has a value". The most basic forms of expressions are constants and variables. When you type "$a = 5", you're assigning '5' into $a. '5', obviously, has the value 5, or in other words '5' is an expression with the value of 5 (in this case, '5' is an integer constant).

Back to If Statements

Let's see what they look like in PHP:

if (expression) {

// code to execute if expression evaluates to TRUE

}

If we expand on that further, it looks more like this:

<?php

// Set some variables

$a = 20;

$b = 50;

if ($a < $b) {

echo "Yep! $a is certainly less than $b.";

}

?>

As you can see, we are using the "less than" symbol (<) to check if the variable $a is smaller than the variable $b. If the expression is TRUE, then PHP will echo the text "Yep! 20 is certainly less than 50."

If statements can be very powerful, but these are just some very basic examples to get you started.

Lecture 17: Else

We've figured out how to execute some code if an expression evaluates to TRUE, but what about when the expression evaluates to FALSE? Often you'll want to execute some code if a certain condition has not been met.

This is where Else comes in to play. Look at Else as an extension of the If statement. The syntax looks like this:

if (expression) {

// code to execute if TRUE

} else {

// code to execute if FALSE

}

Now, let's take a look at a real-world example:

<?php

$fav_fruit = "orange";

if ($fav_fruit == "pineapple") {

echo "YAY! Pineapple is the best.";

} else {

echo "So, you like oranges...";

}

?>

Not all "equals" are created equal

It's good to remember that "==" is different than "=". The former means is equal to while the latter assigns a value to a variable. For example:

Lecture 18: Else if

There's one last piece in the IF / ELSE puzzle. It's called ELSEIF (pronounced "Else If"). ELSEIF is a kind of combination of IF and ELSE. PHP.net puts it nicely:

Like ELSE, it extends an IF statement to execute a different statement in case the original IF expression evaluates to FALSE. However, unlike ELSE, it will execute that alternative expression only if the ELSEIF conditional expression evaluates to TRUE.

If the above explanation is as clear as mud, the syntax looks like this:

if (expression) {

// code to execute if the above expression is TRUE

} elseif (different expression) {

/* code to execute if first expression is FALSE

but the ELSEIF expression is TRUE */

} else {

/* code to execute if neither

of the above expressions are TRUE */

}

Now, if we added some real PHP, it would look like this:

<?php

$native_language = "Spanish";

if ($native_language == "French") {

echo "Bonjour! Vouz parlez Français.";

} elseif ($native_language == "Spanish") {

echo "¡Hola! Usted habla Español.";

} else {

echo "Hello! You probably speak English.";

}

?>

Here's the commented code:

<?php

// Setting the variable

$native_language = "Spanish";

// IF native language is French

if ($native_language == "French") {

// Echo some french!

echo "Bonjour! Vouz parlez Français.";

// ELSEIF native language is Spanish

} elseif ($native_language == "Spanish") {

// Echo some spanish!

echo "¡Hola! Usted habla Español.";

// ELSE native language is neither of the above

} else {

// Echo some english!

echo "Hello! You probably speak English.";

}

?>

Lecture 19: Get Your Hands Dirty

In this lecture, we're going to build a simple PHP script that utilizes the skills we've learned in this section: If Statements, Else and Elseif.

Lecture 20: Comparison Operators

At this point, we've been playing with PHP Variables, Arrays, and If Statements. In nearly every lecture so far, we've seen the "=" symbol. You probably have a basic understanding that it sets a value to a variable, like so:

$myName= "Brad";

In the PHP world, the = symbol is called an "assignment operator". It basically "assigns" the value on the right to the variable on the left. There are many assignment operators, but we'll get into those once we've been introduced to the many other types of operators in PHP.

First, we will start with the "comparison operator".

Comparison operators allow you to compare multiple elements. You can compare whether elements are:

• Equal
• Exactly Equal (Identical)
• Greater Than
• Less Than
• Plus a few more combinations of the above

Here is a handy table, provided by PHP.net

Here is an example of how you would use one of the above comparison operators:

$yearsOnEarth = 14;

if ($yearsOnEarth <= 25) {

echo "Your age is less than or equal to 25!";

}

Lecture 21: Logical Operators

Logical Operators are just that: logical! It's like speaking english. They are very helpful when you need your If / Else / Elseif statements to be a little more complex. Check out this table, provided by PHP.net:

Here is an example of how you would use one of the above logical operators:

$username = "johnnyboy";

$password = "qwerty";

if ($username == 'johnnyboy' && $password == 'qwerty') {

// username and password are correct

} else {

echo "Your username and password combination are incorrect";

}

Lecture 22: Arithmetic Operators

This is where we start getting into some math! It's very basic, but incredibly useful. Check out this table, provided by PHP.net:

The modulus operator is usually a pretty confusing concept at first, but mathforum.org provides a pretty good explanation here:

The "mod" operator in computer languages is simply the remainder. For example,

17 mod 3 = 2

because

17 / 3 = 5 rem 2

which in turn means

17 = 3 * 5 + 2

Here is an example of how you would use one of the above arithmetic operators:

<?php

$birthYear = 1988;

$thisYear = date('Y');

$myAge = ($thisYear - 1988);

echo $myAge;

?>

Lecture 23: String Operators

This one's nice and simple: there are only two string operators. The first one is called the concatenation operator ".", which combines the value of the right argument with the left argument. Let's look at it like this:

$a = "Hola ";

$b = $a . "Mi Amigos!";

echo $b; // This prints "Hola Mi Amigos!"

The second operator is the concatenating assignment operator ".=", which appends the value in the right with the value in the left, like this:

$a = "Hola ";

$a .= "Mi Amigos!";

echo $a; // This prints "Hola Mi Amigos!"

The concatenating assignment operator is considered an "Assignment Operator" which we will be learning more about in the next lecture.

Lecture 24: Assignment Operators

Assignment Operators "assign" values from the right argument to the left argument — usually in the form of variables. The basic assignment operator is "=", which assigns the value on the right to the variable on the left. Here is a table of more assignment operators:

Here's an example of how to use one of the above operators:

<?php

$a = 71;

$b = 36;

$a -= $b;

echo $a; // Prints 35

?>

Lecture 25: While Loop

When coding PHP, loops can be fantastic! Basically, you can write a piece of code to repeat itself again and again until a certain condition has been met. There are a few types of loops in PHP, in this lecture we'll learn about While Loops.

Here's how a while loop works:

while (condition is true) {

// execute code

}

At this point, you probably have no idea how to actually use a while loop in PHP. That's okay. Let's dive into how you actually use it.

Let's say you want PHP to echo the numbers from 10 to 20. First you need to set a variable with your starting number:

<?php

// Set a variable with your starting number

$startingNum = 10;

?>

Then you need to start your while loop with a condition. In this case, we want our condition to say "while my starting number ($startingNum) is less than or equal to 20, the condition is true".

To help clarify — as long as $startingNum is less than or equal to 20, keep on looping!

<?php

// Set a variable with your starting number

$startingNum = 10;

// While $startingNum is less than or equal to 20

while ($startingNum <= 20) {

// execute code

}

?>

You may be thinking: "our starting number is 10, it will always be less than 20, dumbo!".

Well, each time we loop through our function, we will tell PHP to increment our starting number by 1. Therefore, eventually our starting number will be equal to 20!

Our condition says to stop looping once our starting number is larger than 20. We need to do this to prevent an infinite loop — something you most definitely don't want! An infinite loop means your function will literally run forever, which can freeze up your computer.

So, let's tell PHP to echo our $startingNum variable, then increment the variable by 1:

<?php

// Set a variable with your starting number

$startingNum = 10;

// While $startingNum is less than or equal to 20

while ($startingNum <= 20) {

// Echo the variable on the screen

// We'll also concatenate a <br> tag at the end

echo $startingNum . "<br>";

// Then increment the value by 1

$startingNum++;

}

?>

In PHP, you can increment and decrement variables like so:

$a++;	adds 1 to the value of the variable $a each time through
$a--;	subtracts 1 from the value of the variable $a each time through

If coded correctly, this code should echo the numbers 10 to 20 on your screen, and stop at 20. Keep in mind, you can use any of the operators we've used in our past lectures as the conditions that need to be met in the while loop.

Lecture 26: For Loop

For Loops are a little trickier to wrap your head around, so hang in there!

The for loop is used when you know in advance how many times the script should run. — w3schools

The syntax looks like so:

for (initialize counter; test if TRUE; increment counter) {

// execute code

}

Essentially, the For Loop will:

1. Initialize where the loop will start counting by adding a value to a variable
2. Evaluate a certain condition to test if the condition is either TRUE or FALSE (if the condition is FALSE, the loop will stop running)
3. Increment the value by 1 each time we loop through

So, if we want to have our For Loop spit out the numbers 0 to 20, we would code the following:

for ($a = 0; $a <= 20; $a++) {

echo "Number: $a <br>";

}

If coded correctly, this code should echo the numbers 0 to 20 on your screen, and stop at 20.

Lecture 27: Foreach Loop

The Foreach Loop! This loop is a very popular loop, and is used extensively in database-driven websites. The purpose of a Foreach Loop is to "loop through each key/value pair in an array" (w3schools).

The syntax looks like so:

foreach ($array as $value) {

// execute code

}

Basically, here's what happens during each loop iteration:

1. Assign value of current array element to $value
2. $value is echoed on the screen
3. The array pointer then moves to the next element within the array
4. Repeat from beginning until final array element

Let's use a real-world example of how to use a Foreach Loop:

// We need to create an array

// Let's resurrect our array of moustaches

$moustaches = array("Handlebar", "Salvador Dali", "Fu Manchu");

// Loop through the $moustaches array

foreach ($moustaches as $moustache) {

// Output each individual value

echo "I love the $moustache <br>";

}

If coded correctly, this should echo the three moustaches in the array on your screen.

Lecture 28: Do / While Loop

The Do While Loop is a bit like the While Loop, but there's one major difference: the While Loop will only start if the condition is TRUE; whereas the Do While Loop will always execute the first time, and then evaluate whether the condition is TRUE afterwards.

Here's what the syntax looks like:

do {

// execute code

} while ( condition to be met );

Let's look at a real example:

// Set a variable

$i = 1;

do {

// Do this code

echo "Number: $i <br>";

$i++;

}

// Then evaluate this condition

// Repeat loop if TRUE

while ( $i <= 10 );

If coded correctly, this should echo the numbers 1 to 10 on your screen.

Lecture 29: Intro to PHP Functions

If you've made it this far, congratulations are in order! We've covered a lot of ground, and our PHP coding skills are becoming much more refined and skillful!

I'm going to go ahead and say that functions are the Meat n' Potatoes (vegetarian version: Beans n' Rice) of most programming languages; they are fundamental when cooking a tasty PHP dinner!

In PHP, there is a massive library (over 1000) of baked-in functions—pun intended—that do everything from printing text on your screen to adding information to a database, and much more!

It's good to know that there are two types of PHP functions: Built-in PHP Functions, and Custom Functions (you can write your own custom PHP functions!).

Remember echo and print? Those little guys are functions!

Important Facts about Functions

A function is a block of statements that can be used repeatedly in a program.

A function will not execute immediately when a page loads.

A function will be executed by a call to the function.

— w3schools

Let's take a look at the basic syntax of a function:

function functionName() {

// execute code

}

Please note: A function name can start with a letter or underscore (not a number). — w3schools

Hot tip: You can name the function whatever you wish! Just try and have it reflect what the function actually does.

PHP sort() Function

Let's take a quick look at the built-in PHP sort() Function. This function allows us to sort an array in alphabetical order.

First, let's create an array:

// Custom array

$dinner = array("Meat", "Potatoes", "Beans", "Rice");

Now let's run our array through the sort() function:

// Custom array

$dinner = array("Meat", "Potatoes", "Beans", "Rice");

// Add the array as a parameter to sort() function

sort($dinner);

Now all we have to do is echo our array on the screen, using a Foreach loop:

// Custom array

$dinner = array("Meat", "Potatoes", "Beans", "Rice");

// Add the array as a parameter to sort() function

sort($dinner);

// Echo the sorted array

foreach ($dinner as $ingredient) {

echo "$ingredient <br>";

}

If coded correctly, the above will echo the array in alphabetical order:

Beans
Meat
Potatoes
Rice

If you're looking to sort your array in reverse order, you can use the PHP rsort()function. Feel free to read more about the sort function, and other sorting functions here.

We won't be covering all of the built-in PHP functions in this course, because that would take an incredibly long time. Besides, it's fun to be in a situation where you're programming and then you think "Hey! I wonder if there's a PHP function that will do this for me?" — this is why I'll leave you with the curiosity to experiment. Google is your best friend, and you may also refer to this directory.

Lecture 30: Custom Functions

While PHP has a massive library of built-in functions you have at your disposal, sometimes you need to build your own functions — for both small and large tasks.

Think of a custom functions as a mini-program that performs an action for you — better yet, think of a custom function as a cute little robot that does a specific task you tell it to do!

Let's look at the basic syntax of a function:

<?php

function myCustomFunction() {

// things my custom function will do

// go in here

}

?>

To build your custom function, you need to type function myCustomFunction(). Keep in mind that "myCustomFunction()" can be whatever words you want them to be, but no spaces allowed. Then add opening and closing curly brackets (or curly braces, as some call it). In between the curly brackets is where you define what your function will perform.

There are two important things to know about functions:

1. There are functions that require "arguments", and;
2. There are functions that don't require "arguments".

Let's start by building a custom function that does not require an argument.

<?php

// Build the function

function hangTen() {

echo "Surf's up! Grab your board!";

}

// Call the function

hangTen();

?>

Lecture 31: Simple Arguments

Functions can be incredibly powerful, because you can program them to do almost anything you want them to. One important step in making your functions even smarter is to use "arguments" within your function. Not the type of argument where you and a friend are bickering about a disagreement, I'm talking about arguments within functions — two very different things.

Think of an argument like a variable. Your program can pass extra information to your functions using arguments. You specify your arguments within the parenthesis after your function name, and you can have as many as you want, as long as they're comma separated.

Let's look at an example of a function with a single argument:

<?php

function hangTen($location) {

echo "We're surfing in $location!<br>";

}

hangTen("Hawaii");

hangTen("California");

hangTen("Newfoundland");

?>

So, in the above example, we're passing an argument to the hangTen() function. Later in our script, we call our function several times with a string of text within each parenthesis, and each time we call our function with a new argument value, that value will display on the screen along with the text we provided in our function.

The output will look like this:

We're surfing in Hawaii!
We're surfing in California!
We're surfing in Newfoundland!

Let's look at an example with two arguments:

All we did here was add another argument, separated by comma, then when we called our multiplyTogether() function later in the script, we provided two values to take the place of our $val1 and $val2 arguments.

The result?

The product of the two numbers is: 378

Lecture 32: The Final Website

In this lecture, we take a look at the final PHP website we'll be building based on the knowledge we've learned throughout this course.

Lecture 33: Code a Basic Webpage Layout

In this lecture, we code a standard HTML webpage.

Lecture 34: Templating a Global Header & Footer

In this lecture, we begin creating PHP header and footer templates. We also learn how to create a dynamic navigation menu using arrays.

Lecture 35: Dynamic Copyright & Hours of Operation

In this lecture, we learn how to create a dynamic copyright date, and also how to install a PHP plugin to let our users know if our store is currently open or closes.

Lecture 36: Code a Team Member Array & Template

In this lecture we code a PHP template that we use to display our team members.

Lecture 37: Code a Menu Array & Template

In this lecture, we build an array for our restaurant menu items, and build a template to display our menu items.

Lecture 38: Understanding $_GET

When the URL the browser requests includes a query string (anything after a question mark), the $_GET collection is created automatically. The string on the left side of an equals sign ( = ) becomes a variable name, and the thing on the right side of the equals sign becomes that variable's value.

So, for example: in our previous lecture we have a link on our menu.php page that navigates to "dish.php?item=mexican-barbacoa". That URL will navigate to the dish.php template (which we have not created yet) and the $_GET collection will create a variable called "item" with the value of "mexican-barbacoa". We can then use that value to do something specific on our dish.php template.

It could be as simple as "echo mexican-barbacoa" or, "display specific information in an array with the key of 'mexican-barbacoa'" This is what we will be doing in our next lecture.

Lecture 39: Code a Menu Item Dynamic Template

In this lecture, we code a PHP template that will allow us to populate the page with dynamic information based on the query string passed into the URL.

Lecture 40: Code a Simple Contact Form

In this lecture, we code a simple HTML contact form. In the upcoming lectures, we will learn how to submit the form, and perform simple validation on inputs.

Lecture 41: Understanding $_POST

In this lecture, we learn the basics of $_POST and how we will use it for PHP forms.

Lecture 42: Simple Form Validation & Submission (Part 1)

In this lecture, we start integrating PHP into our HTML contact form.

Lecture 43: Simple Form Validation & Submission (Part 2)

In this lecture, we continue from where we left off in Part 1.

Lecture 44: Uploading our Website Live on the Web

In this lecture, we learn how to get set up with some web hosting that supports PHP websites, and we upload our website live to a real web server.

Required resource to upload live on the web:

A Hosting Package (I recommend Justhost)

Lecture 45: Wrap Up & Where To Go From Here

Thanks for taking the course! I hope you've found value in it.

This lecture gives you some next steps to take on your web development journey.

Cheers!

Brad