PHP method for generating random numbers without duplicates _ php instance

This article summarizes five methods to generate random numbers that do not repeat. Methods 1, 2, and 3 are commonly used by me, and the method is four or five to reach du Niang. There are still some other methods. You are also welcome to let us know the missing methods. The common progress can be applied to both Web applications, WAP or mobile applications, and random numbers. In recent small projects, I often need to deal with random numbers or random arrays. Therefore, I would like to summarize several common methods for generating non-repeated random numbers in PHP.

Method 1:

The Code is as follows:

<? Php
$ Numbers = range (1, 50 );
// Shuffle will immediately disrupt the array order
Shuffle ($ numbers );
// Array_slice retrieves a segment of the array
$ Num = 6;
$ Result = array_slice ($ numbers, 0, $ num );
Print_r ($ result );
?>

Method 2:

The Code is as follows:

<? Php
$ Numbers = range (1, 20 );
// Broadcast the seed of the random number generator, which is dispensable and does not affect the test result.
Srand (float) microtime () * 1000000 );
Shuffle ($ numbers );
// Skip the first value of the list (the index is saved)
While (list (, $ number) = each ($ numbers )){
Echo "$ number ";
}
?>

Method 3:

The Code is as follows:

<? Php
Function NoRand ($ begin = 0, $ end = 20, $ limit = 5 ){
$ Rand_array = range ($ begin, $ end );
Shuffle ($ rand_array); // call the random array arrangement function.
Return array_slice ($ rand_array, 0, $ limit); // the first $ limit
}
Print_r (NoRand ());
?>

Five distinct values can be randomly generated between 1 and 20.

Method 4:

The Code is as follows:

<? Php
$ Tmp = array ();
While (count ($ tmp) <5 ){
$ Tmp [] = mt_rand (1, 20 );
$ Tmp = array_unique ($ tmp );
}
Print_r ($ tmp );
?>

Method 5:

The Code is as follows:

<? Php
$ Tmp = range (1, 30 );
Print_r (array_rand ($ tmp, 10 ));
?>

This may be simpler (ps: If the step is specified in the range, you must note whether the second parameter of array_rand exceeds the length of $ tmp ).

PHP provides a wealth of array functions, most of which can be used to generate random numbers from the array perspective. Of course, if you have a better method, please let me know. This article is also worth mentioning.