PHP rand() Function
In this chapter you will learn:
- Definition for PHP rand() Function
- Syntax for PHP rand() Function
- Parameter for PHP rand() Function
- Return for PHP rand() Function
- Note for PHP rand() Function
- Example - Generate Random number
- Example - Display Random picture
Definition
The rand() function returns random numbers. If you call it with no parameters, it will
return a number between 0 and the value returned by getrandmax().
Syntax
PHP rand() Function has the following syntax.
int rand ( [int min, int max] ) Parameter
| Parameter | Is Required | Description |
|---|---|---|
| min | Optional. | Lowest number to be returned. Default is 0 |
| max | Optional. | Highest number to be returned. Default is getrandmax() |
If you supply it with two parameters, rand() will use those numbers as the upper and
lower limits of the random number, inclusive of those values. That is, if you specify 1
and 3, the value could be 1, 2, or 3.
Return
| Item | Value |
|---|---|
| Return Value | A random integer between min (or 0) and max (or getrandmax() inclusive) |
| Return Type | Integer |
Note
If you want a random integer between 10 and 100 (inclusive), use rand (10,100). The mt_rand() function produces a better random value, and is 4 times faster than rand().
Example 1
<?PHP
$random = rand();
$randrange = rand(1,10);
?>
The numbers generated by rand() are more
predictable than using the mt_rand() function.
Example 2
Display Random picture
<html>//j a v a 2 s. com
<body>
<?php
srand( microtime() * 1000000 );
$num = rand( 1, 4 );
switch( $num ){
case 1 : $car = "a.jpg"; $url="a.php"; break;
case 2 : $car = "f.jpg"; $url="f.php"; break;
case 3 : $car = "j.jpg"; $url = "j.php"; break;
case 4 : $car = "p.jpg"; $url = "p.php"; break;
}
$banner = "<a href='$url'>";
$banner.= "<img src='$car'";
$banner.= "width='380' height='110'>";
$banner.="</a>";
echo( $banner );
?>
</body>
</html>
Next chapter...
What you will learn in the next chapter:
- Definition for PHP round() Function
- Syntax for PHP round() Function
- Parameter for PHP round() Function
- Return for PHP round() Function
- Note for PHP round() Function
- Example - round value in PHP
- Example - Round value and set number of decimal places to keep
- Example - Round float with round mode