Suppose you have created a PHP script called test1.php. To launch this script, you need to add the script name after localhost in your browser. So instead of this:
You would type this: http://localhost/test1.php
You don’t type the name of the wamp folder, however. This would be wrong, for example:
OK, we’ll assume that everything is now up and running.
Variables in PHP
A variable is just a storage area. You put things into your storage areas (variables) so that you can use and manipulate them in your programmes. Things you’ll want to store are numbers and text.
If you’re ok with the idea of variables, then you can move on. If not, think of them like this. Suppose you want to catalogue your clothing collection. You enlist two people to help you, a man and a woman. These two people are going to be your storage areas. They are going to hold things for you, while you tally up what you own. The man and the woman, then, are variables.
You count how many coats you have, and then give these to the man. You count how many shoes you have, and give these to the woman. Unfortunately, you have a bad memory. The question is, which one of your people (variables) holds the coats and which one holds the shoes? To help you remember, you can give your people names! You could call them something like this:
But it’s entirely up to you what names you give your people (variables). If you like, they could be called this:
OK, so your people (variables) now have a name. But it’s no good just giving them a name. They are going to be doing some work for you, so you need to tell them what they will be doing.
Putting value into variables
The man is going to be holding the coats. But we can specify how many coats he will be holding. If you have ten coats to give him, then you do the “telling” like this:
mr_coats = 10
So, the variable name comes first; then an equals sign. After the equals sign, you tell your variable what it will be doing. Holding the number 10, in our case
However, you’re learning PHP, so there’s something missing. Two things, actually. First, your people (variables) need a dollar sign at the beginning (people are like that). So it would be this:
$mr_coats = 10
$mrs_shoes = 25;
So, $mrs_shoes is holding a value of 25. If we then wanted to add up how many items of clothes we have so far, we could set up a new variable (Note the dollar sign at the beginning of the new variable):
We can then add up the coats and the shoes. You add up in PHP like this:
$total_clothes = $mr_coats + $mrs_shoes;
Remember, $mr_coats is holding a value of 10, and $mrs_shoes is holding a value of 25. If you use a plus sign, PHP thinks you want to add up. So it will work out the total for you. The answer will then get stored in our new variable, the one we’ve called $total_clothes. You can also add up like this:
$total_clothes = 10 + 35;
Again, PHP will see the plus sign and add the two together for you. Of course, you can add up more than two items:
$total_clothes = 10 + 35 + 7 + 38 + 1250;
But the idea is the same – PHP will see plus signs and then add things up. The answer is then stored in your variable name, the one to the left of the equals sign.
In the next part, we’ll take a look at how to put text into variables.
Putting Text into Variables
In the previous section, you saw how to put numbers into variables. But you can also put text into your variables. Suppose you want to know something about the coats you own. Are they Winter coats? Jackets? Summer coats? You decide to catalogue this, as well. You can put direct text into your variables. You do it in a similar way to storing numbers:
$coats1 = “Winter Coats”;
Again, our variable name starts with a dollar sign ($). We’ve then given it the name coats1. The equals sign follows the variable name. After the equals sign, however, we have direct text – Winter Coats. But notice the double quotation marks around our text. If you don’t surround your direct text with quotation marks, then you’ll get errors. You can, however, use single quotes instead of double quotes. So you can do this:
$coats1 = ‘Winter Coats’;
But you can’t do this:
$coats1 = ‘Winter Coats”;
The direct text will then get stored in the variable to the left of the equals sign.
So, to recap, variables are storage areas. You use these storage areas to manipulate things like text and numbers. You’ll be using variables a lot in PHP sites.