What is the method to generate non-repeating random numbers in PHP

How to generate non-repeating random numbers in PHP: first shuffle the order of the array; then take a certain section of the array, the code is [$numbers = range (1,50);shuffle ($numbers) ;$result = array_slice($numbers..】.

PHP method to generate non-repeating random numbers:

Whether it is a Web application, a WAP or a mobile application, random numbers have their place. In several small projects I have been exposed to recently, I often need to deal with random numbers or random arrays, so I have no idea how PHP generates them. Let’s summarize several commonly used methods for repeating random numbers.

Method one:

The code is as follows:

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

Method two:

The code is as follows:

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

Method three:

The code is as follows:

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

The above can be randomized between 1-20 Generate 5 unique values

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 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).

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