PHPBuilder - Math & Number Handling in PHP - The ABCs of PHP Part 6



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Math & Number Handling in PHP - The ABCs of PHP Part 6

by: PHP Builder Staff
|
April 21, 2009

Last time we looked at text and strings in variables, in this episode we're going to continue with our exploration of PHP variables and delve deeper into math and number handling in PHP.
Using numbers is not much different to using text and strings, you allocate variables and fill them in, using exactly the same techniques as you do using strings & text.
Basic Operators
The standard arithmetic operators are available in PHP and these are the same as in any other language:
  • + Addition of numbers (20+10)
  • - Subtraction of numbers (20-10)
  • * Multiplication of numbers (20*10)
  • / Division of numbers (20/10)
When setting up or assigning variables, you can set the initial value to the result of a mathematical equation, as in the following example:
	$result = 2+2; // $result will be equal to 4
For subtraction and addition there's also a very handy shortcut or two which are great for loop handling, these shortcuts are used by appending either a double + or a double - after the variable name:
  • $a = 1; // $a equals to 1
  • $a++; // $a equals 2
  • $a--; // $a once again equals 1
The second operator can also be specified as '=num' :
  • $a = 1; // $a equals 1
  • $a+=2; // $a equals 3
  • $a-=2; // $a back to 1
Why would you want to use the shorthand form? Well it turns out that using this method is great for loops and repetitive commands (we'll cover this more in a later article) such as the for loop:
	for($count=0;$count<10;$count++)
	{
		// Repeat what ever goes here 10 times
	}
In that small example, we start at 0, and keep adding one to $count as long as we are still less than 10.
An IMPORTANT note here, is that a lot of counting structures in PHP start at 0, so in the previous example we are counting from 0 to 9, which is 10 times round before it stops. If we'd changed it to <11 in the middle part, we would have actually performed 11 counts.

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