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 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 randomly generate 5 non-repeating numbers between 1-20 The value of

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).

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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