random string generator php

1function generateRandomString($length = 25) {
2    $characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
3    $charactersLength = strlen($characters);
4    $randomString = '';
5    for ($i = 0; $i < $length; $i++) {
6        $randomString .= $characters[rand(0, $charactersLength - 1)];
7    }
8    return $randomString;
9}
10//usage 
11$myRandomString = generateRandomString(5);

1//generates 13 character random unique alphanumeric id
2echo uniqid();
3//output - 5e6d873a4f597

1function generateRandomString($length = 10) {
2    $characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
3    $charactersLength = strlen($characters);
4    $randomString = '';
5    for ($i = 0; $i < $length; $i++) {
6        $randomString .= $characters[rand(0, $charactersLength - 1)];
7    }
8    return $randomString;
9}
10
11Output the random string with the call below:
12
13// Echo the random string.
14// Optionally, you can give it a desired string length.
15echo generateRandomString();

1function rand_str() {
2    $characters = '0123456789-=+{}[]:;@#~.?/>,<|\!"£$%^&*()abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
3    $randomstr = '';
4    for ($i = 0; $i < random_int(50, 100); $i++) {
5      $randomstr .= $characters[rand(0, strlen($characters) - 1)];
6    }
7    return $randomstr;
8  }

1/**
2 * Generate a random string, using a cryptographically secure 
3 * pseudorandom number generator (random_int)
4 *
5 * This function uses type hints now (PHP 7+ only), but it was originally
6 * written for PHP 5 as well.
7 * 
8 * For PHP 7, random_int is a PHP core function
9 * For PHP 5.x, depends on https://github.com/paragonie/random_compat
10 * 
11 * @param int $length      How many characters do we want?
12 * @param string $keyspace A string of all possible characters
13 *                         to select from
14 * @return string
15 */
16function random_str(
17    int $length = 64,
18    string $keyspace = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
19): string {
20    if ($length < 1) {
21        throw new \RangeException("Length must be a positive integer");
22    }
23    $pieces = [];
24    $max = mb_strlen($keyspace, '8bit') - 1;
25    for ($i = 0; $i < $length; ++$i) {
26        $pieces []= $keyspace[random_int(0, $max)];
27    }
28    return implode('', $pieces);
29}
30

1<?php
2    function RandomString()
3    {
4        $characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
5        $randstring = '';
6        for ($i = 0; $i < 10; $i++) {
7            $randstring = $characters[rand(0, strlen($characters))];
8        }
9        return $randstring;
10    }
11
12    RandomString();
13    echo $randstring;