<?php

function pass($level=2,$length=6) {

    $chars[1] = "023456789abcdefghijmnopqrstuvwxyz";
    $chars[2] = "2345678开发者_如何转开发9abcdefghijmnopqrstuvwxyzABCDEFGHIJKLMNPQRSTUVWXYZ";

    $i = 0;
    $str = "";

    while ($i<=$length) {
        $str .= $chars[$level][mt_rand(0,strlen($chars[$level]))];
        $i++;
    }

    return $str;

}

echo pass(2, 7);

?>

When I call the function, I really can't set anything up. pass(2,7) is the same length as pass(1, 9). It's all level 2 and some length. What's wrong?

---

The other answers seem to ignore the fact that strings are treated as arrays of characters in php (see the section String access and modification by character).

Your script worked fine for me with two modifications:

First:

You are referencing a character randomly from 0 to the length of the string. This doesn't work, string arrays are 0-indexed, and therefore 1 less than the length.

Try:

$str .= $chars[$level][mt_rand(0,strlen($chars[$level]) - 1)];

Second:

You are looping through this procedure from 0 to the length specified, meaning that it will loop $length + 1 times.

Try:

while ($i < $length) {

this worked perfectly for me.

Here's sample output:

print pass(2, 7) //prints IR5YgGD
print pass(1, 10) //prints d2eyq547gy

---

• You need -1 to not overflow.

• You can use substr to [] to access.

  function pass($level=1,$length=6) {
  
  $chars = array();
  $chars[0] = "023456789abcdefghijmnopqrstuvwxyz";
  $chars[1] = "23456789abcdefghijmnopqrstuvwxyzABCDEFGHIJKLMNPQRSTUVWXYZ";
  
  $i = 0;
  $str = "";
  while ($i<$length) 
  {
      $index = mt_rand(0,strlen($chars[$level])-1);//It's inclusive you need -1
      $str .= substr($chars[$level],$index,1);//Take the index with 1 for a single char
      //You can also use:
      //$str .= $chars[$level][$index];
      $i++;
  }
  
  return $str;
  
  }
  
  echo pass(0, 7);//Start at 0 because array start at 0. So it's your Level1
  echo pass(1, 7);//Start with 1, it's your Level2    
  ?>
  

---

This will work fine

<?php

function pass($level=2,$length=6) {

$chars[1] = array("0","2","3","4","5","6","7","8","9","a","b","c","d","e","f","g","h","i","j","m","n","o","p","q","r","s","t","u","v","w","x","y","z");
$chars[2] = array("2","3","4","5","6","7","8","9","a","b","c","d","e","f","g","h","i","j","m","n","o","p","q","r","s","t","u","v","w","x","y","z","A","B","C","D","E","F","G","H","I","J","K","L","M","N,"P","Q","R",""S","T","U","V","W","X","Y","Z");

$i = 0;
$str = "";
while ($i<=$length) {
    $str .= $chars[$level][mt_rand(0,count($chars[$level])-1)];
    $i++;
    }

return $str;

}

echo pass(2, 7);

?>

---

Here's what I got. I define the length mt_rand() needs, and then use curly braces {} to extract the character at the random index:

function pass($level=2, $length=6) {

    $chars[1] = "023456789abcdefghijmnopqrstuvwxyz";
    $chars[2] = "23456789abcdefghijmnopqrstuvwxyzABCDEFGHIJKLMNPQRSTUVWXYZ";

    $i = 0;
    $str = "";
    $charLen = strlen($chars[$level]) -1;

    while ($i<$length) {
        $str .= $chars[$level]{mt_rand(0,$charLen)};
        $i++;
    }

    return $str;
}

$result = pass(2, 21);