Basic PHP: The Full Language Introduction 2

Dec 03, 2017 The Village Geek Apache, Build Site, HTML, Introduction, PHP Comment(s)

Ello, ello, ello ...

How are you ?

Did you manage to make that Lobola money? Oh Lobola is a South African tradition, where a man pays/gives gifts/monies to the wife's family. It's so much fun.

"Alright, Okay ..." - Denzel Washington

In this tutorial, we'll be looking at the PHP variable scope. Before we move on, please note that PHP variables can be declared anywhere in a script. Meaning there is no designated time or place during the loading of a page when a variable should be set, you can create and use a PHP variable just about anywhere in a page. A variable's scope is the area of the script where a variable can either be used, accessed or referenced. This is the part of the script where you can call the variable and use it. This means that you can't use or access a variable everywhere in a script or page.

Alright take a breather Khomotso, let it sink in a bit and come back :)

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

PHP has three main variable scopes:

local global static

Alright before you loose your marbles and run around the neighbourhood screaming the words "I want a banana" in a high pitched voice, let's first take a breather and introduce the wonders that are FUNCTIONS. An understanding of functions will make it much easier for you to understand variable scopes. Functions are a collection of one or more PHP statements stored in a block, that can be called/referenced and used at multiple points of a PHP script for multiple times. They are essentially a way of creating reusable code. PHP has a lot of built in functions that have proven to be very helpful, but in this tutorial we'll be looking at user defined functions. Your own functions.

PHP Functions

Once again, a function is a block of statements that can be used repeatedly in a program. A PHP function is defined as shown below

<?php
    function nameFunction() {
        //function code to be returned here inside
    }
?>

Simple right?! ... Once the function is declared, it can be called anywhere in the code and reused as many times as needed. The code below shows you how you can call and use the function :

<?php
    function sayHello(){
        echo 'hello world1!';
    }

    //calling the function
    sayHello();

    //calling the function will print 'hello'
?>

As usual Pedro, create a new PHP file called 'functions.php', get your ide/text editor ready, because we're about to get our code on. Alright copy and paste the code below, and let's get cracking ....

<?php

    function printText(){
        echo 'this text is from the function';
    }

    printText();
?>

Load the page in your browser and Raj is your uncle. The text in your function is printed. Let's argue a little bit shall we. Yes, toasted coconut marshmallows are the best of the marshmallow family. Functions accept what we call arguments, these are the values that can be passed to the function to be used within the function for whichever purpose the code deems worthy. Let's look at a high level representation of this concept shall we .

<?php

    function testArguments($name){

        echo 'your name is '.$name.'!';
    }

    // caliing function with our argument
    testArguments('Thandi');
?>

Now copy and replace the code in your 'functions.php' file will ya. Reload the page in your browser and voila! ... your name is printed as is shown in the code. Be mindful that a function can take as many arguments as your pretty brain can take. like so :

<?php

    function testArguments($name, $lastName){
        echo 'Your name is '.$name.' '.$lastName;
    }

    testArguments('Thandi', 'Swanepoel');

?>

Default values for our arguments, these are the values that will be used instead of our arguments in case they are empty. Like so ...

<?php

    function defaultArguments($name = 'default name'){
        echo 'The name value is '. $name;
    }

    defaultArguments('Sthembile');
    defaultArguments();
    defaultArguments('Danng Ma!');
?>

Replace, save, reload ... and it's showtime!! Now let's show you the ability of a function to return a response of some sort. I know , I know, it's a lot to take in on a sunny sunday afternoon but this is the last part ... I swear or whatever makes you comfortable. Let's do numbers this time shall we? ... let's return some stuff

<?php 

    function addition($x, $y){
        $sum = $x + $y;
        return $sum;
    }

    echo addition(5, 1);
?>

This will return the sum of the two arguments and print them for us on the page. Okay take some time out, and take a walk to the pond my friend. You've had your share of the teaching in this tutorial. Sorry Ombre ...

"Functions are a collection of one or more php statements stored in a block, that can be called/referenced and used at multiple points of a PHP script for multiple times"
The Village Geek

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

Play around with the code will ya ... It'll be a good decompression for you.

Talk to you next time ...

Cape Town, South Africa

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TUTORIAL Basic PHP: The Full Language Introduction 2

Basic PHP: The Full Language Introduction 2

PHP Functions

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