Basic PHP : The Full Language Introduction 1

Oct 26, 2017 The Village Geek Build Site, Introduction, PHP Comment(s)

Thobela Kgoshi ...

Please note that this tutorial is part of the Build Your Own Site series of tutorials. Feel free to restart the series.

"Alright, alright, alright ..." - Matthew McConaughey ...

Let's get into it Partner.

In the last tutorial of the series; 'Build Your Own Site', we elaborated a lot more on HTML, and helped built our first Form on an HTML Page. We talked a little about submitting forms and needing PHP to process that form submission. And so here we are; learning some of that PHP "good-good" to get you start.

For a little more intro into the language , please read : *what-is-php?*. In this tutorial you'll be writng actual code and seeing some of the easy ways to use the language. In our Build-Site Series, we'll be using PHP to process data on the back-end/server side of things. This will be when a user submits a form. There will be data submitted and received, and then we will use the PHP file/script to handle that data. We will not be using it much on our front-end/client side of things. We do this, to let you not only learn good coding practice, but also to learn how to keep your code clean. Important point before we begin, PHP only runs on an HTTP Request i.e when a page loads or a form is submitted etc. So it doesn't react to user input like a button pressed as do other languages like javascript. It doesn't bind to the Browser's events. Meaning PHP is not a user facing or a user interfacing language, we'll be using html and javascript for that. For the purposes of this small site we're building; the front-end, meaning the form in our html file will be used for user interaction. We will load the html page with the form. The user will fill the form and press the submit button. the data will be passed to our php file, which will process the data for us.

"Alright, alright, alright ..." - Kevin Hart's Dad

Now that we have talked extensively about how all of this is going to work, let's get back to the topic at hand shall we; learning how to use the PHP language.

PHP Tags

As we've indicated in a lot of our previous tutorials, PHP is written between php tags, like so:

<?php  exit('soul train'); //php here  ?>
<!DOCTYPE HTML>
<html>
<head>
<title>PHP FOOL!!</title>
</head>

<body>
    php above fool
</body>

</html>

You know the drill Pablo, create a file called "basic.php", save it and load it in your browser. Now let's get cracking partner ... We're gonna add php tags and get coding right away

<?php
    echo 'hello world';
?>

Save the file and load it Sammy, "http://localhost/basic.php". You'll see the text "hello world", on the otherwise white and empty page. Okay ... let's get going ... As with many languages, we're first going to learn how to declare variables in PHP

DECLARING VARIABLES

Variables in PHP are declared with the $ sign, because we're all about that moolla booiiyyy. Naaahh it's just a convention that was adapted at the creation of the language. Look at the example below

<?php 
    $stuff = "Hello World";
    echo stuff;
?>

The text "Hello World" is now stored in the variable "$stuff", so when we print it on the page using the echo function, we'll get the "Hello World" text as before. Copy the code above and replace the one in your "basic.php" file. Reload the page again and voila! Think of variables as value storage containers, they're called variables because their values are variable, their values can be changed. varied. Variables values, can be assigned, like we've done above, and a variable's value can be changed along the way within the code. Eg:

<?php 
    $stuff = "Hello World";
    echo $stuff;

    $stuff = "New value";
    echo $stuff;
?>

K Ramon, update your "basic.php" and behold the wonder of updating a variable. PHP variables, like other languages, can be concatenated with existing text and printed on the page. Look at our updated code below.

<?php 
    $stuff = "Hello World";
    echo "At first you have to say ".$stuff;
?>

Notice how we add the '.' to combine the string and the $stuff variable. There are other ways to combine strings, php variables , and html tags in the PHP language. But for now, this is all you need to know. We'll use and look at a couple of those methods throughout these tutorials. So hang tied soldier, you're about to get educated!! PHP variables can store numeric values as well as string values.PHP can also perform mathematical manipulations like addition, substraction etc. In the code below we're gonna store a numeric value and the add it to another.

<?php 

    $num = 5;

    $sum = $num + 5; // this will give 10

    $difference = $num - 2; // this will give 3

    $multiplication = $num * 2; // this will give 10

    $division = $num / 1; // this will give you 5

?>

We'll be using a lot of PHP variables in these tutorials, so please look at these basic PHP variable rules below.

Rules for PHP variables:

A variable starts with the $ sign, followed by the name of the variable A variable name must start with a letter or the underscore character A variable name cannot start with a number character A variable name can only contain alpha-numeric characters and underscores (A-z, 0-9, and _ ) Variable names are case-sensitive $age and $AGE are two different variables according to PHP.

"We'll be using a lot of PHP variables in these tutorials, so please look at these basic PHP variable rules."
The Village Geek

"Alright, alright, alright ..." - Matthew McConaughey

We've learnt enough for one tutorial Betsy, go ahead and get some lemonade and a biscuit, and maybe take a long walk to the park will ya :)

In the next tutorial we'll continue in our quest to get you more familiar with the basics of PHP.

Cape Town, South Africa

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TUTORIAL Basic PHP : The Full Language Introduction 1