How to generate unique serial numbers in php

How to generate unique serial numbers in php: You can use the built-in function [mt_rand()] to achieve this. The [mt_rand()] function is used to generate random integers, for example, to generate a number between 10 and 100. A random integer between , the specific code is: [mt_rand(10, 100)].

php provides us with the function mt_rand() specially used to generate random numbers, which uses the Mersenne Twister algorithm to generate random integers.

Tip: This function is a better choice for generating random values, returning results 4 times faster than the rand() function.

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Example:

Generate a value between 10 and 100 (including 10 and 100) Random integer

mt_rand (10,100)

Function syntax:

mt_rand();
or
mt_rand(min,max);

Parameters:

• ##min Optional. Specifies the minimum number to return. The default is 0.​

• #max Optional. Specifies the maximum number to return.

Return value:

A random integer between min (or 0) and max (or mt_getrandmax()) (including boundary values). If max < min returns FALSE.

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Code implementation:

//生成随机码
    function GetRandStr($len=10){
        $chars = array(
            "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k",
            "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v",
            "w", "x", "y", "z", "A", "B", "C", "D", "E", "F", "G",
            "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R",
            "S", "T", "U", "V", "W", "X", "Y", "Z", "0", "1", "2",
            "3", "4", "5", "6", "7", "8", "9"
        );
        $charsLen = count($chars) - 1;
        shuffle($chars);
        $output = "";
        for ($i=0; $i<$len; $i++)
        {
            $output .= $chars[mt_rand(0, $charsLen)];
        }
        return $output;
    }
    //生成不在$arr中的序列号
    function getUniqueSerial($arr){
        $str = GetRandStr(64);
        if(in_array($str, $arr)){
            $str = getUniqueSerial($arr);
        }
        return $str;  
    }

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