Women in Technology

Article:		Working with Files in PHP, Part 3
Subject:		line !== 'false'
Date:		2003-03-12 15:22:26
From:		anonymous2
The article states that you need to use the !== comparison operator: "Without this type of comparison, the while loop would end prematurely if a directory (or filename) existed with the name of false" I can't seem to get the loop to stop when it encounters a directory named false even if I leave out the !== and use != instead. Using windows.

Showing messages 1 through 2 of 2.

• line !== 'false'
  2003-03-12 16:39:03  John Coggeshall | [View]
  
  
  Although this behavior may work (not using the 'identical' comparison and just using a standard comparison) it is not to be relied on. For instance:
  
  $myfile = "0"; // a filename whose name is '0'
  if($myfile == false) {
  echo "$myfile is false\n";
  } else {
  echo "$myfile is true.\n";
  }
  
  In this case, the string '0' will be evaluated as an integer value '0' which is in turn a boolean false. In order for this to behave properly you'd need to use the identical comparison === operator.
  
  John
• line !== 'false'
  2005-03-17 10:11:01  Cerro [View]
  
  
  I was looking for some code to list the directory content with PHP3. The problem that i had was that i had a subdirectory named 0. Since in PHP3 there is no !== operator i did like this:
  
  function ListDir($dir)
  {
  if ((file_exists($dir)) && ($dh = opendir($dir)))
  {
  while (($file = readdir($dh)) || (((string) $file == "0") || ($file != false)))
  echo($file);
  closedir($dh);
  }
  }
  
  In this case the problem directory name is "0" but you can add "false" to the condition.