PHP函数无法正常运行

Question

<?php

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

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

    $i = 0;
    $str = "";

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

    return $str;

}

echo pass(2, 7);

?>

当我调用该函数时，我真的无法设置任何东西。 pass（2,7）与pass（1,9）的长度相同。这都是2级和一些长度。怎么了？

Answer 1

• 你需要-1不要溢出。

• 您可以使用substr []来访问。

  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    
  ?>
  

Answer 2

其他答案似乎忽略了strings are treated as arrays of characters in php这一事实（参见字符串访问和按字符修改部分）。

通过两次修改，您的脚本对我来说很好：

第一：

您正在从0到字符串长度随机引用一个字符。这不起作用，字符串数组是0索引的，因此比长度小1。

尝试：

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

第二

您正在循环执行此过程，从0到指定的长度，这意味着它将循环$length + 1次。

尝试：

while ($i < $length) {

这对我来说非常合适。

以下是示例输出：

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

Answer 3

这样可以正常使用

<?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);

?>

Answer 4

这是我得到的。我定义了mt_rand()的长度需求，然后使用花括号{}来提取随机索引处的字符：

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);