How to generate unique random numbers in PHP

How to generate unique random numbers in PHP

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 how to generate non-repeating random numbers in PHP (ps: Methods 1, 4, and 5 are my Commonly used ones, the rest are collected from the Internet)

Method 1:

<span><?php 
$numbers = range (1,50); <span>//shuffle 将数组顺序随即打乱 </span> shuffle ($numbers); <span>//array_slice 取该数组中的某一段 </span> $num=6; 
$result = array_slice($numbers,0,$num); 
print_r($result); 
?></span>

Method 2:

<span><?php 
$numbers = range (1,20); <span>//播下随机数发生器种子，可有可无，测试后对结果没有影响</span> srand ((<span>float</span>)microtime()*1000000); 
shuffle ($numbers); <span>//跳过list第一个值（保存的是索引）</span> <span>while</span> (<span>list</span>(, $number) = each ($numbers)) { <span>echo</span> <span>"$number "</span>; 
} 
?></span>

Method 3:

<span><?php <span>function</span> NoRand($begin=0,$end=20,$limit=5){ 
$rand_array=range($begin,$end); 
shuffle($rand_array);<span>//调用现成的数组随机排列函数 </span> <span>return</span> array_slice($rand_array,0,$limit);<span>//截取前$limit个 </span> } 
print_r(NoRand()); 
?></span>

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

Method 4:

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

Method 5:

<span><?php 
$tmp = range(1,30);
print_r(array_rand($tmp,10));
?></span>

This may be simpler than calling it (ps: 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).

The above introduces how to generate non-repeating random numbers in PHP, including the relevant content. I hope it will be helpful to friends who are interested in PHP tutorials.