PHP String Exercises : Generate simple random password from a specified string

Last update on June 02 2025 13:01:40 (UTC/GMT +8 hours)

9. Generate Random Password Without rand()

Write a PHP script to generate simple random password [do not use rand() function] from a given string.

Sample string: '1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZabcefghijklmnopqrstuvwxyz'
Note : Password length may be 6, 7, 8 etc.

Sample Solution:

PHP Code:

<?php
// Define a function named password_generate that takes the number of characters as input
function password_generate($chars) 
{
  // Define a string containing all possible characters for the password
  $data = '1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZabcefghijklmnopqrstuvwxyz';
  // Shuffle the characters in the string and extract a substring of length $chars
  return substr(str_shuffle($data), 0, $chars);
}
// Call the password_generate function with 7 characters and echo the generated password
echo password_generate(7)."\n";
?>

Output:

89Qp3AK

Explanation:

In the exercise above,

<?php: This tag indicates the beginning of a PHP script.
Function password_generate($chars): This line defines a PHP function named "password_generate()" that takes one parameter '$chars', which represents the number of characters in the password to be generated.
{: Opening curly brace indicates the beginning of the function body.
$data = '1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZabcefghijklmnopqrstuvwxyz';: This line creates a string named '$data' containing a pool of characters from which the password will be generated. It includes digits (0-9), uppercase letters (A-Z), and lowercase letters (a-z).
return substr(str_shuffle($data), 0, $chars);: This line generates a random password by performing the following steps:

str_shuffle($data): Randomly shuffles the characters in the '$data' string.
substr(...): Takes a substring of the shuffled characters, starting from index 0 and having a length of '$chars'. This ensures that the generated password has the specified number of characters.
return ...;: Returns the generated password from the function.

}: Closing curly brace indicates the end of the function body.
echo password_generate(7)."\n";: This line calls the "password_generate()" function with an argument of 7, indicating that a password with 7 characters should be generated. It then echoes the generated password followed by a newline character.
?>: This tag indicates the end of the PHP script.

Flowchart :

For more Practice: Solve these Related Problems:

Write a PHP function that generates a random password of a given length using the shuffle() function on a character set string.
Write a PHP script to create a secure random password by shuffling a predefined string and then slicing a substring for the password.
Write a PHP program to generate multiple random passwords using a non-rand() method, and then output them in a list with varying lengths.
Write a PHP function to generate a password by splitting a character pool into an array, shuffling the array, and then joining a subset of characters.

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PHP Code Editor:

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