Home Backend Development PHP Tutorial Three ways to generate random strings in PHP

Three ways to generate random strings in PHP

Jun 07, 2018 am 11:17 AM

This article mainly introduces three methods of generating random strings in PHP. Interested friends can refer to it. I hope it will be helpful to everyone.

Method 1

1. Generate a random integer between 33 and 126, such as 35.

2. Convert 35 into the corresponding ASCII code character, such as 35 corresponding to #.

3. Repeat the above steps 1 and 2 n times to connect to an n-digit password.

This algorithm mainly uses two functions. The mt_rand (int $min, int $max) function is used to generate random integers, where $min – $max is the range of ASCII codes, here it is 33-126, The range can be adjusted as needed. For example, 97-122 bits in the ASCII code table correspond to the English letters a-z. For details, please refer to the ASCII code table; the chr (int $ascii) function is used to convert the corresponding integer $ascii into the corresponding character.

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function create_password($pw_length

{

$randpwd = ”;

for ($i = 0; $i < $pw_length; $i++)

{

$randpwd .= chr(mt_rand(33, 126));

}

return $randpwd;

}

// 调用该函数,传递长度参数$pw_length = 6

echo create_password(6);

Copy after login

Method 2

1. Preset a string $chars, including a – z, A – Z, 0 – 9, and some special characters.

2. Randomly pick a character from the $chars string.

3. Repeat the second step n times to get a password of length n.

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function generate_password( $length = 8 ) {

// 密码字符集,可任意添加你需要的字符

$chars = ‘abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!@#$%^&*()-_ []{}<>~`+=,.;:/?|&#39;;

$password = ”;

for ( $i = 0; $i < $length; $i++ )

{

// 这里提供两种字符获取方式

// 第一种是使用 substr 截取$chars中的任意一位字符;

// 第二种是取字符数组 $chars 的任意元素

// $password .= substr($chars, mt_rand(0, strlen($chars) – 1), 1);

$password .= $chars[ mt_rand(0, strlen($chars) - 1) ];

}

return $password;

}

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Method 3

1. Preset a character array $chars, including a – z, A – Z, 0 – 9, and some special characters.

2. Use array_rand() to randomly select $length elements from the array $chars.

3. According to the obtained key name array $keys, take out the characters from the array $chars and concatenate the string. The disadvantage of this method is that the same characters will not be retrieved repeatedly.

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function make_password( $length = 8 )

{

  

// 密码字符集,可任意添加你需要的字符

$chars = array(‘a&#39;, ‘b&#39;, ‘c&#39;, ‘d&#39;, ‘e&#39;, ‘f&#39;, ‘g&#39;, ‘h&#39;,

‘i&#39;, ‘j&#39;, ‘k&#39;, ‘l&#39;,&#39;m&#39;, ‘n&#39;, ‘o&#39;, ‘p&#39;, ‘q&#39;, ‘r&#39;, &#39;s&#39;,

‘t&#39;, ‘u&#39;, ‘v&#39;, ‘w&#39;, ‘x&#39;, ‘y&#39;,&#39;z&#39;, ‘A&#39;, ‘B&#39;, ‘C&#39;, ‘D&#39;,

‘E&#39;, ‘F&#39;, ‘G&#39;, ‘H&#39;, ‘I&#39;, ‘J&#39;, ‘K&#39;, ‘L&#39;,&#39;M&#39;, ‘N&#39;, ‘O&#39;,

‘P&#39;, ‘Q&#39;, ‘R&#39;, ‘S&#39;, ‘T&#39;, ‘U&#39;, ‘V&#39;, ‘W&#39;, ‘X&#39;, ‘Y&#39;,&#39;Z&#39;,

‘0′, ‘1′, ‘2′, ‘3′, ‘4′, ‘5′, ‘6′, ‘7′, ‘8′, ‘9′, ‘!&#39;,

‘@&#39;,&#39;#&#39;, ‘$&#39;, ‘%&#39;, ‘^&#39;, ‘&&#39;, ‘*&#39;, ‘(‘, ‘)&#39;, ‘-&#39;, ‘_&#39;,

‘[&#39;, &#39;]‘, ‘{‘, ‘}&#39;, ‘<&#39;, ‘>&#39;, ‘~&#39;, ‘`&#39;, ‘+&#39;, ‘=&#39;, ‘,&#39;,

‘.&#39;, ‘;&#39;, ‘:&#39;, ‘/&#39;, ‘?&#39;, ‘|&#39;);

  

// 在 $chars 中随机取 $length 个数组元素键名

$keys = ($chars, $length);

$password = ”;

for($i = 0; $i < $length; $i++)

{

// 将 $length 个数组元素连接成字符串

$password .= $chars[$keys[$i]];

}

return $password;

}

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Time efficiency comparison

We use the following PHP code to calculate the running time of the above 3 random password generation functions to generate a 6-digit password , and then conduct a simple comparison of their time efficiency. The final result is:

Method one: 9.8943710327148E-5 seconds
Method two: 9.6797943115234E-5 seconds
Method three: 0.00017499923706055 seconds
You can see the method The execution time of Method 1 and Method 2 are similar, while the running time of Method 3 is slightly longer.

Summary: The above is the entire content of this article, I hope it will be helpful to everyone's study.

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