Summary of methods for generating non-repeating random numbers in PHP

This article summarizes 5 methods for generating non-repeating random numbers. Among them, methods 1, 2, and 3 are my commonly used methods, and methods 4 and 5 come to Du Niang. There are still other methods, and everyone is welcome to tell us about the missing methods, so that we can make progress together

Whether it is a web application, a WAP or a mobile application, random numbers have their place. In several small projects that I have been exposed to recently, I often need to deal with random numbers or random arrays. Therefore, I will summarize some common methods for generating non-repeating random numbers in PHP.

Method 1:

Copy code The code is as follows:

$numbers = range (1,50);
//shuffle shuffles the order of the array
shuffle ($numbers);
//array_slice takes a certain segment of the array
$num =6;
$result = array_slice($numbers,0,$num);
print_r($result);
?>

Method 2:

Copy code The code is as follows:

$numbers = range (1,20);
//Sow the random number generator seed, optional, it will have no impact on the results after testing
srand ((float)microtime()*1000000);
shuffle ($numbers);
//Skip the first value of list (the index is saved)
while (list(, $number) = each ($numbers)) {
echo "$number ";
}
?>

Method three:

Copy code The code is as follows:

function NoRand($begin=0,$end=20,$limit=5){
$rand_array=range($begin,$end);
shuffle($rand_array); //Call the ready-made array random arrangement function
return array_slice($rand_array,0,$limit);//Intercept the first $limit pieces
}
print_r(NoRand());
?> ;

The above can randomly generate 5 non-repeating values ​​between 1-20

Method 4:

Copy code The code is as follows:

$tmp=array();
while(count($tmp)<5){
$tmp[]=mt_rand(1,20);
$tmp=array_unique($tmp);
}
print_r($tmp);
?>

Method five:

Copy code The code is as follows:

$tmp = range(1,30);
print_r(array_rand($tmp,10));
?>

This may be simpler than calling it (ps: If in If the step size is specified in the range, you must pay attention to whether the second parameter of array_rand exceeds the length of $tmp).

PHP provides a very rich array function. Most random numbers can be generated from the perspective of arrays. Of course, if you have a better method, please let us know. This article can be considered as an introduction.

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