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Does anyone have a sample PHP program that generates a random alphanumeric string of a specified length?

Hey folks,

I'm working on a project where I need to generate random alphanumeric strings of a specified length using PHP. I've been searching online for a while now, but haven't had much luck finding a suitable solution.

Is there anyone here who could provide me with a sample PHP program that accomplishes this task? It would be really helpful if the program allows me to specify the length of the string as well.

Thanks in advance!

All Replies


Hey there!

I've actually encountered a similar requirement in one of my projects recently. What I did was use the `str_shuffle` and `substr` functions in PHP to generate the random alphanumeric string.

Here's a code snippet that you can modify to suit your needs:

function generateRandomString($length) {
$characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
$charactersLength = strlen($characters);
$randomString = '';

for ($i = 0; $i < $length; $i++) {
$randomString .= $characters[rand(0, $charactersLength - 1)];

return $randomString;

$desiredLength = 10; // You can modify this to your desired length
$randomString = generateRandomString($desiredLength);

echo "Random alphanumeric string of length $desiredLength: $randomString";

In this example, the function `generateRandomString` accepts the desired length as a parameter. It creates a character pool which consists of all numbers and both lowercase and uppercase letters. The characters are shuffled using `str_shuffle` and concatenated to create the random string of the specified length.

I hope this helps you achieve what you're looking for! Let me know if you have any further questions.


Hey everyone,

I've been lurking around this thread and I thought I'd chime in with my solution to generating random alphanumeric strings in PHP.

What I found useful is the `uniqid` function that PHP provides. This function generates a unique identifier based on the current time in microseconds. By default, it produces a 13-character string that includes alphanumeric characters and a hyphen. However, we can remove the hyphen to make it purely alphanumeric.

Here's an example of how you can achieve that:

$desiredLength = 8; // You can change this to your desired length

$randomString = uniqid('', true); // Generates a unique identifier
$randomString = str_replace('.', '', $randomString); // Removes the dot separator

$randomString = substr($randomString, 0, $desiredLength); // Trims down to the desired length

echo "Random alphanumeric string of length $desiredLength: $randomString";

In this snippet, the `uniqid` function generates a unique identifier with a microtime value and a more_entropy parameter set to true. We then use `str_replace` to remove the dot separator from the identifier. Finally, `substr` is used to trim the string down to the desired length.

Feel free to adjust the `$desiredLength` variable to your needs.

I hope this alternative method proves helpful to those looking for a different approach. Happy coding!

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