PHP Random Number
How to generate random number or id
Rand () function is used to generate a random number it takes two integer optional parameters. You can use mt_rand () function that generates a random number faster than and rand function function.
Simple method to generate unique number within specific range
<?php
$r=rand(200,500);
printf("Unique number =%d
",$r);
?>
- Example
- Run
Explanation
rand() function is a PHP built-in function that generates a unique number. If you want to generate a unique number within a range, then define the start and end point of random number. If you define the start and end point, then the unique number will be in between.
Start point = 10
End point = 100
Number can =11
Number can =99
Number cannot =101
Number cannot =09
If you have not decide the start and end point, then rand function automatically create a unique number without any range, it’s totally depend on function.
Generate random number without specific range
<?php
$r=rand();
printf(" Number =%d",$r);
?>
- Example
- Run
Explanation
In this example, a random number is created without any range. It can be any number like 20, 5289, 120 etc.
Generate random numbers using loop
<?php $min=10; $max="100"; echo "Number between 10 to 100
"; for($i=0;$i<=10;$i++) { $r=rand($min,$max); printf("Nnumber =%d
",$r); } ?>
- Example
- Run
Explanation
In this example, the start point is 10 and the end point is 100 and in seventh the line there is a simple echo statement that display the statement. According to the line number 11 to 14 is a for loop that’s run 10 times, a variable $r store the random number and printf function print 10 number.
Generate random number using date
<?php
$currentdate=date('Ymd');
$date_range=20120314;
$number=rand($date_range , $currentdate);
echo $number;
?>
- Example
- Run
Explanation
In the above example, start point is the current date and the end point is specified in this program, so the number could be 20120312 etc.
Complex random number
<?php
$time1=time();
$t=$time1;
$random= rand(0,999999999);
$a= $t+$random;
printf(" Random number =%d",$a);
echo "
";
$un= uniqid();
$conct = $a.$un;
//its also refer a unique id
printf("Random number =%d
",$conct);
$ud = md5($conct.$un);
echo "But its more accurate=";
echo $ud;
?>
- Example
- Run
Explanation
In this example first store the current date in $time1 variable, then create a unique number from zero to 99999999 and then add unique number and time, it’s also a good random number. After that call uniqid (its create a unique id) function to a variable $un and concatenate $un and $a, call md5 (calculates the MD5 hash of a string). it’s very secure.
Random id refer as product id in many websites.
