Méthode PHP pour convertir un identifiant numérique en identifiant lettre

Cet article partage principalement avec vous la méthode de conversion d'un identifiant numérique en identifiant lettre en PHP. J'espère qu'il pourra vous aider.

alphaID(12354）；  //会将数字转换为字母。  
alphaID('PpQXn7COf',true）；
//会将字母ID转换为对应的数字。  
alphaID(12354,false,6）；//指定生成字母ID的长度为6.

<?php  
/** 
 * Translates a number to a short alhanumeric version 
 * 
 * Translated any number up to 9007199254740992 
 * to a shorter version in letters e.g.: 
 * 9007199254740989 --> PpQXn7COf 
 * 
 * specifiying the second argument true, it will 
 * translate back e.g.: 
 * PpQXn7COf --> 9007199254740989 
 * 
 * this function is based on any2dec && dec2any by 
 * fragmer[at]mail[dot]ru 
 * see: http://nl3.php.net/manual/en/function.base-convert.php#52450 
 * 
 * If you want the alphaID to be at least 3 letter long, use the 
 * $pad_up = 3 argument 
 * 
 * In most cases this is better than totally random ID generators 
 * because this can easily avoid duplicate ID&#39;s. 
 * For example if you correlate the alpha ID to an auto incrementing ID 
 * in your database, you&#39;re done. 
 * 
 * The reverse is done because it makes it slightly more cryptic, 
 * but it also makes it easier to spread lots of IDs in different 
 * directories on your filesystem. Example: 
 * $part1 = substr($alpha_id,0,1); 
 * $part2 = substr($alpha_id,1,1); 
 * $part3 = substr($alpha_id,2,strlen($alpha_id)); 
 * $destindir = "/".$part1."/".$part2."/".$part3; 
 * // by reversing, directories are more evenly spread out. The 
 * // first 26 directories already occupy 26 main levels 
 * 
 * more info on limitation: 
 * - http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/165372 
 * 
 * if you really need this for bigger numbers you probably have to look 
 * at things like: http://theserverpages.com/php/manual/en/ref.bc.php 
 * or: http://theserverpages.com/php/manual/en/ref.gmp.php 
 * but I haven&#39;t really dugg into this. If you have more info on those 
 * matters feel free to leave a comment. 
 * 
 * @author  Kevin van Zonneveld <kevin@vanzonneveld.net> 
 * @author  Simon Franz 
 * @author  Deadfish 
 * @copyright 2008 Kevin van Zonneveld (http://kevin.vanzonneveld.net) 
 * @license   http://www.opensource.org/licenses/bsd-license.php New BSD Licence 
 * @version   SVN: Release: $Id: alphaID.inc.php 344 2009-06-10 17:43:59Z kevin $ 
 * @link    http://kevin.vanzonneveld.net/ 
 * 
 * @param mixed   $in    String or long input to translate 
 * @param boolean $to_num  Reverses translation when true 
 * @param mixed   $pad_up  Number or boolean padds the result up to a specified length 
 * @param string  $passKey Supplying a password makes it harder to calculate the original ID 
 * 
 * @return mixed string or long 
 */  
function alphaID($in, $to_num = false, $pad_up = false, $passKey = null)  
{  
  $index = "abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";  
  if ($passKey !== null) {  
    // Although this function&#39;s purpose is to just make the  
    // ID short - and not so much secure,  
    // with this patch by Simon Franz (http://blog.snaky.org/)  
    // you can optionally supply a password to make it harder  
    // to calculate the corresponding numeric ID  

    for ($n = 0; $n<strlen($index); $n++) {  
      $i[] = substr( $index,$n ,1);  
    }  

    $passhash = hash(&#39;sha256&#39;,$passKey);  
    $passhash = (strlen($passhash) < strlen($index))  
      ? hash(&#39;sha512&#39;,$passKey)  
      : $passhash;  

    for ($n=0; $n < strlen($index); $n++) {  
      $p[] =  substr($passhash, $n ,1);  
    }  

    array_multisort($p,  SORT_DESC, $i);  
    $index = implode($i);  
  }  

  $base  = strlen($index);  

  if ($to_num) {  
    // Digital number  <<--  alphabet letter code  
    $in  = strrev($in);  
    $out = 0;  
    $len = strlen($in) - 1;  
    for ($t = 0; $t <= $len; $t++) {  
      $bcpow = bcpow($base, $len - $t);  
      $out   = $out + strpos($index, substr($in, $t, 1)) * $bcpow;  
    }  

    if (is_numeric($pad_up)) {  
      $pad_up--;  
      if ($pad_up > 0) {  
        $out -= pow($base, $pad_up);  
      }  
    }  
    $out = sprintf(&#39;%F&#39;, $out);  
    $out = substr($out, 0, strpos($out, &#39;.&#39;));  
  } else {  
    // Digital number  -->>  alphabet letter code  
    if (is_numeric($pad_up)) {  
      $pad_up--;  
      if ($pad_up > 0) {  
        $in += pow($base, $pad_up);  
      }  
    }  

    $out = "";  
    for ($t = floor(log($in, $base)); $t >= 0; $t--) {  
      $bcp = bcpow($base, $t);  
      $a   = floor($in / $bcp) % $base;  
      $out = $out . substr($index, $a, 1);  
      $in  = $in - ($a * $bcp);  
    }  
    $out = strrev($out); // reverse  
  }  

  return $out;  
}

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Implémentation PHP de la conversion de l'ID numérique en lettre ID_PHP tutoriel

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