RandomStringList

<?php

$list = new RandomStringList(1000, 4);
$list->output();

class RandomStringList
{
  // remove l,I,O,0,1
  const CHARACTERS = "abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ23456789";

  protected $number = 0;
  protected $length = 0;
  protected $list = array();

  public function __construct($number = 100, $length=4)
  {
    $this->number = $number;
    $this->length = $length;

    for($i=0; $i<$this->number; $i++){
      $this->list[] = $this->getString();
    }
  }

  public function output()
  {
    echo implode(',', $this->list);
  }

  public function createString()
  {
    $num = strlen(self::CHARACTERS);
    $result = '';
    for($i=0; $i<$this->length; $i++){
      $result .= substr(self::CHARACTERS, mt_rand(0, $num-1), 1);
    }
    return $result;
  }
  
  protected function getString()
  {
    $string = $this->createString($this->length);
    // check duplicated item in list
    if(in_array($string, $this->list)){
      $string = $this->getString();
    }
    return $string;
  }
}