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

By PHP Builder Staff
on 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:
		// 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.