An SEO’s Intro to Web Dev PHP

An SEO’s Intro to Web Dev 2
Just PHP

Troy Boileau | SEO & Inbound Marketing Consultant

For Powered by Search | January 2014

We’re in business because we believe that great brands need
both voice and visibility in order to connect people with what
matters.
A boutique, full-service digital marketing agency in Toronto,
Powered by Search is a PROFIT HOT 50-ranked agency that
delivers search engine optimization, pay per click advertising,
local search, social media marketing, and online reputation
management services.
Some of our clients...

Featured in...

What is PHP?
Variables and Arrays
Functions
Loops and Conditions

What is PHP?
And Why Should I Care?
PHP is a server-side programming language that’s used on 81% of all
websites. But what does “Server-Side” mean?
There’s two sides to this coin: server-side and client-side.
Client-side code is run by a web browser and other technology on the user’s
computer (like how Adobe Flash Player, a program on your computer, is
used to run video files in your browser). Client-side code is usually HTML,
CSS and JavaScript. The user downloads the code, the browser runs it.
Server-side code is run by the web server. Since the server usually has
access to a database and other hidden files and programs, it can do neat
things like dynamically pull in information for a page. The server runs its
code, then the users downloads it, then the browser runs client-side code.

What is PHP?
When you’re poking around in a client’s website trying to fix some SEO issue
or another you’re going to run into this:

What is PHP?
And unless you have a general understanding of what this means and how it
works, you’re going to have to go to a developer whose time we bill in the
three digits per hour as well as waste everyone’s time for simple issues.
Also, if you get a basic grasp of PHP you’ll understand every programming
language in the world.
Oh, and that little <?php is just the opening tag to any PHP segment.
All PHP code segments are wrapped in this:
<?php
?>

What is PHP?
One Final Note
You’ll forget all of this. Just try to understand it as we zip through.
Go do the Code Academy courses. If after that you’re still not excited about
programming, that’s fine. At least you’ll recognize little bits of code and be
able to look them up on Google and get the gist of everything rather than
running to an overwhelmed developer.
If you are excited, good for you. Programming is about creating. Go build
something big and you’ll learn more than any book will teach you.

Building Blocks of Programming
HTML lets us show users information like this:
<p>Hello World!</p>
That’s fine, we can do that with PHP too:
What’s with the echo bit, you ask? It’s a command that forces PHP to output
what follows. If you don’t use “echo” then nothing will get sent to the user.
This code sends the following HTML to the browser:
<p>Hello World!</p>

That’s a pretty lame use of PHP though. Let’s start using variables which are
containers for different types of data (numbers, words, arrays, anything).
Then you can call that same information back anywhere in the code, just by
using the variable name.


Variables are fundamental to programming. Strings (what
we call any kind of text) need to be wrapped in quotation
marks “” while you can declare a numerical variable just
need the number:

Arrays
Imagine a variable as a name associated to a box. This one holds the value
of 12 but it could just as easily be “Pineapples.”

An array is a name associated to many boxes.

Each box in an array is opened with a key, which is pretty easy to figure out.
The key is a number starting at 0 from the first array element to the second
(1), the third (2), and so on.
To output “11” the code would be echo $array[0];. “golum” would be echo
$array[4];. What would the code be for “44”?

Arrays
Here’s a quick look at creating an array and what its guts look like. The code
is:

And here’s what shows up in the browser’s source:

Arrays
Why arrays though?
Well, it’ll make a lot more sense later when we get into loops, but consider
how valuable it would be to have a list of 600 names stored in variables with
different names.
Probably not very.
You might as well have an array called $names with 600 elements in it.

Functions and DRY
Don’t Repeat Yourself
One of the most common, most basic programming rules is “Don’t Repeat
Yourself.”
For example, if I know I’m going to repeat the URL of a site a million times
over, I’m going to just store the URL in a variable.

There are lots of great reasons to respect DRY code.
1. Since I’m using a variable rather than manually putting the URL in each
time, I don’t have the human error issue.
2. If we drop the www. bit of the URL, I just change one line of code rather
than potentially hundreds.
3. I don’t have to write out (or remember) the whole URL over and over
again.

Functions and DRY
Fun with Functions...
Functions are another useful feature for keeping your code neat. They have
three parts:
1. A Name
2. Input Variables (optional)
3. A Return Value (optional)
They all have the same format, too:

Functions and DRY
Here’s a pretty useless function to demonstrate how they work:

The first bit is the function declaration. It’s where I declare what I want the
function to do. The second bit, where I call “what_i_do()” is a function call.
You can only declare a function once, but you can call it a million times.

Functions and DRY
Let’s make it a bit more interesting. Notice how I’m wrapping the input
variable in HTML paragraph tags. Let’s not do that. I’m pretty lazy so I want
the function to do that for me.

Now we’re using all three parts of the function. The name, the input
variable and the return value. And the function does something useful and
time-saving; it wraps a string in a paragraph tag.

If This Then That
Now we’ve got variables and functions, the next step is conditionals. We
make conditional decisions all of the time; if there’s no milk, then I’ll go buy
milk. In PHP, we can do the same thing. It just looks different.

The bit inside the round brackets is a boolean expression. That sounds
complex but all it means is that whatever you put in those brackets has to
be either true or false. The complicated bit arises when we start talking
about boolean operators.

Boolean Operators
Let’s go over the most useful three operators really fast:
1. == (equal to)
2. < (less than)
3. > (greater than)
Notice how the first on the list isn’t a single equal sign? That’s because PHP
considers a single equal sign to mean “MAKE the left side equal the right
side,” e.g. “$var = 1” MAKES the variable $var hold the value of 1. If you
want a boolean (true/false) response then you’re always looking for the
double equal sign.

Boolean Operators
Now for some examples. Just say “true” or “false.”
1>2
2 == 1
1+7>9
2/1>1
$var = 7
$var == 9

Boolean McOperators
Now for some examples. Just say “true” or “false.”
If (1 > 2) {
}
If (2 == 1) {
}
If (1 + 7 > 9) {
}
If (2 / 1 > 1) {
}
$var = 7
If ($var == 9) {
}

Marrying Conditions and Functions
So, if this boolean operator is true, then do whatever.

This code creates a function called test that accepts an input variable called
name. It checks to see if the name is Spartacus, and if so outputs “I AM
SPARTACUS”. Of the four names we put in, there’s only one Spartacus, so
the output will be “I AM SPARTACUS” just the once.

Conditions and Functions
But I think everyone was Spartacus in the movie, so let’s just subtly change
it using an else statement, which appends onto an if statement but the code
within it only runs if the conditional in the if statement was false.

Let’s trace this code once. We send in “Timothy.” The code goes, “Is
‘Timothy’ that same as ‘Spartacus’? No? Then let’s use the code in the else
statement and output ‘I’m Spartacus’.”

Loops
Loops are the last bit. Certain types of loops can be needlessly complex, but
what they do is loop over a piece of code over and over again until the
condition to break the loop is met. Here’s an example of a type of loop
called a “while loop”:

You should recognize the $number < 3 bit. It’s the same idea as in the if
statement; it returns either true or false. The while statement checks the
boolean statement, and if true it runs the code within the curly brackets,
over and over until the statement is false.

Some Examples

Understanding Your First PHP
Program

Understanding PHP
Everything
Let’s do something simple but... maybe useful isn’t the right word... with
loops, arrays, functions, conditionals, all of this.
Remember arrays? We can use a loop to go through them. First, let me
teach you a new array trick and let you take a look at the array we’re going
to work with.

Assigning a value to the array name followed by [] just adds it to the end of
the array.

Understanding PHP
Everything
So we’ve got this array of names, and we want to know if they’re Spartacus
or not. Let’s go back to our old function that solved this problem, but
change it slightly:

What would the output be if I wrote the line of code:
who_is_spartacus(12);
?

Understanding PHP
Everything
Now we’ve got an array of names and a function that checks one name. This
doesn’t work very well. We need to send just ONE name to the function
from our array...
This is where our loop becomes useful. And I get to teach you something
else! A function called count(), which ... Counts the elements of an array.
If an array has 4 elements, then, count(array_name) will return the number
4. Which you’d expect.
So what happens in this loop?

Understanding PHP
Everything
Now what happens, keeping in mind that $names[0] is equal to “Sarah”?

Understanding PHP
Everything
And what would happen if we, god forbid, did this?

Get Out
....
<3

Stay in Touch
Twitter: @troyfawkes
Google+: google.com/+TroyBoileau
Email: troy@poweredbysearch.com
www.poweredbysearch.com
www.troyfawkes.com

An SEO’s Intro to Web Dev PHP

More Related Content

What's hot

Similar to An SEO’s Intro to Web Dev PHP

Recently uploaded

An SEO’s Intro to Web Dev PHP