How to generate non-repeating random numbers in php

How to generate non-repeating random numbers in php: first create a PHP sample file; then use the "mt_random($min,$max)" method to randomly generate a value in the range; finally use "key- value" exchange, that is, through the uniqueness of the array key, it can be achieved without duplication.

The operating environment of this tutorial: Windows 7 system, PHP version 5.6. This method is suitable for all brands of computers.

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How to produce non-repeating random numbers in PHP

PHP built-in functions are not Repeating random numbers

Requirement: To generate an array, there are 10 elements in this array, all are integers, and they are non-repeating random numbers between 1-60.

Code:

Code example:

<?php   
       
 
        function 
        get_randoms(
        $min
        ,
        $max
        ,
        $num
        ){  
       
 
               
        $count 
        = 0;  
       
 
               
        $res 
        = 
        array
        ();  
       
 
               
        while
        (
        $count
        <
        $num
        ){  
       
 
            
        $res
        [] = mt_random(
        $min
        ,
        $max
        );  
       
 
            
        $res 
        = 
        array_flip
        (
        array_flip
        (
        $res
        ));   
       
 
            
        $count 
        = 
        count
        (
        $res
        );  
       
 
                
        }  
       
 
                
        return 
        $res
        ;  
       
 
         
        }  
       
 
            
       
 
        $result 
        = get_randoms(1,60,10);  
       
 
        ?>

Here he uses $count to count the number of result arrays, and he makes the number of result arrays less than the target in the while loop. number. Through this, we get $count which is an array of target number.

During each cycle, through mt_random($min,$max), a value within the range is randomly obtained and stored in the array $res, and then through two key-value exchanges, that is, through The uniqueness of the array key ensures no duplication.

After I read the code of this logic, I couldn't help but fall into deep thought. What would you do if you didn't know the array_filp function?

To put it bluntly, it uses the uniqueness of the key so that there will be no duplication of random numbers. So can we simplify this problem?

Code example:

<?php   
       
 
        function 
        get_randoms(
        $min
        ,
        $max
        ,
        $num
        ){  
       
 
           
        $count 
        = 0;  
       
 
           
        $res 
        = 
        array
        ();  
       
 
           
        while
        (
        $count
        <
        $num
        ){  
       
 
           
        $key 
        = mt_random(
        $min
        ,
        $max
        );  
       
 
           
        $res
        [
        $key
        ] = 
        $key
        ;  
       
 
           
        $count 
        = 
        count
        (
        $res
        );  
       
 
               
        }  
       
 
               
        return 
        $res
        ;  
       
 
        }  
       
 
        $result 
        = get_randoms(1,60,10);  
       
 
        ?>

This solves this problem completely through the uniqueness of the array key. array_flip will not be used at all.

Summary:

1, because PHP provides a large number of built-in functions, their execution efficiency is very high. When you encounter a problem, try to use it to solve the problem as much as possible. This is convenient and fast.

2, PHP provides a large number of built-in functions, and the execution efficiency is also very high. However, although the efficiency is high, it still takes time to execute.

When you encounter a problem, don't do it blindly. You can first see the essence of the solution so that you can implement it skillfully.

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