我试图在PHP中创建一个随机字符串，我得到绝对没有输出:
<?php
function RandomString()
{
$characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
$randstring = '';
for ($i = 0; $i < 10; $i++) {
$randstring = $characters[rand(0, strlen($characters))];
}
return $randstring;
}
RandomString();
echo $randstring;
我做错了什么?
当前回答
如果您非常害怕输入字母表中的字母，不关心字符串安全性，并且只对字母感兴趣，那么这里有一个简单的解决方案
$alphabets = range ("a", "z");
shuffle ($alphabets);
$randomString = substr(implode ("", $alphabets), 3, 17); // adjust according to desired length
其他回答
下面的函数生成任意长度的伪字符串。
/**
* Returns random string of a given length.
*/
function get_random_string($length) {
$pull = [];
while (count($pull) < $length) {
$pull = array_merge($pull, range(0, 9), range('a', 'z'), range('A', 'Z'));
}
shuffle($pull);
return substr(implode($pull), 0, $length);
}
我想要特定字符和预设长度的伪随机字符串。我希望当前版本的PHP具有最高质量的伪随机性，此时它可以是v5、v6、v7或v8，并且可以使用默认配置或特殊配置。为了解决这种混乱，我在这里选取了其他几个答案，并包含了函数可用性条件。
使用。要全局使用它，给$VALID_ID_CHARS赋值你想要的字符，然后调用它:
$VALID_ID_CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
$myNewRandomId = makeId(6);
function makeId($desiredLen)
{
global $VALID_ID_CHARS;
if ($desiredLen < 1) {
throw new \RangeException("Length must be a positive integer");
}
$vLen = 0;
if (function_exists('mb_strlen')) {
$vLen = mb_strlen($VALID_ID_CHARS, '8bit') - 1;
} else {
$vLen = strlen($VALID_ID_CHARS) - 1;
}
if (function_exists('random_int')) {
$pieces = [];
for ($i = 0; $i < $desiredLen; ++$i) {
$pieces[] = $VALID_ID_CHARS[random_int(0, $vLen)];
}
return implode('', $pieces);
}
if (function_exists('openssl_random_pseudo_bytes')) {
$random = openssl_random_pseudo_bytes($desiredLen);
$id = '';
for ($i = 0; $i < $desiredLen; ++$i) {
$id .= $VALID_ID_CHARS[ord($random[$i]) % $vLen];
}
return $id;
}
http_response_code(500);
die('random id generation failed. either random_int or openssl_random_pseudo_bytes is needed');
}
如果您非常害怕输入字母表中的字母，不关心字符串安全性，并且只对字母感兴趣，那么这里有一个简单的解决方案
$alphabets = range ("a", "z");
shuffle ($alphabets);
$randomString = substr(implode ("", $alphabets), 3, 17); // adjust according to desired length
短的方法。
这里有一些生成随机字符串的最短方法
<?php
echo $my_rand_strng = substr(str_shuffle("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"), -15);
echo substr(md5(rand()), 0, 7);
echo str_shuffle(MD5(microtime()));
?>
具有上面讨论的一些函数的类。
$options['numeric'] = true;
$options['uppercase'] = true;
$options['lowercase'] = true;
$new = new RandomString($options);
class RandomString
{
/**
* @var array
*/
private $default = ['numeric' => true, 'uppercase' => true, 'lowercase' => true];
/**
* @var array
*/
private $options;
/**
* array
*/
private $whitelist = ['numeric', 'uppercase', 'lowercase'];
/**
* RandomString constructor.
*
* @param array $options
*/
public function __construct(array $options = [])
{
$this->options = $this->default;
if(!empty($options))
{
$options = array_intersect_key($options, array_flip($this->whitelist));
if(empty($options))
{
$this->options = $this->default;
}else
{
$this->options = $options;
}
}
}
/**
* @return string
*/
private function returnCharacters(){
$options = $this->options;
$numbers = '0123456789';
$uppercase = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
$lowercase = "abcdefghijklmnopqrstuvwxyz";
$characters = '';
if(isset($options['numeric']) && $options['numeric'] === true){
$characters .= $numbers;
}
if(isset($options['uppercase']) && $options['uppercase'] === true){
$characters .= $uppercase;
}
if(isset($options['lowercase']) && $options['lowercase'] === true){
$characters .= $lowercase;
}
return $characters;
}
/**
* @param $length
* @param $quantity
* @return string
*/
public function randomString($length, $quantity) {
$string = '';
$characters = $this->returnCharacters();
for ($j = 0; $j < $quantity; $j++) {
for($i = 0; $i < $length; $i++){
$string .= $characters[mt_rand(0, strlen($characters) - 1)];
}
$string .= "\n";
}
return $string;
}
/**
* @return array
*/
public function getOptions()
{
return $this->options;
}
/**
* @return mixed
*/
public function getWhitelist()
{
return $this->whitelist;
}
