5 ms·

My complaint about arrays in PHP is warnings for reading a array member that may not exist, such as when reading a form input that might not be there. $foo

• nbpoole 15y ago
  They're notices, not warnings. They can be disabled via a simple call to the error_reporting function. I fundamentally disagree with you though. For me, notices are very useful for identifying typos and other coding mistakes that can lead to incorrect behavior. Consider the following lines of code: $user_info = array( 'id' => 1, 'username' => 'nbpoole', 'is_guess' => false ); if (!$user_info['is_guest']) { echo 'Member stuff'; } When I run that script with error_reporting set to E_ALL, I get an "undefined index" notice pointing me to the line where I do the comparison: at that point, I can track down where in my code I misspelled the word guest. Without the notice, I might not immediately realize that the 'is_guest' index was mis-spelled somewhere.
• kylewpppd 15y ago
  This is exactly what PHP does. Yes, it issues you a notice, not a warning, not an exception. And it does not break execution. Just set your error_reporting variable to a lower level, and you won't get the Notice at all.
• code_duck 15y ago
  You really wouldn't like Python or even stricter languages such as Scala or java, then. In Python, an attempt to access a nonexistent dictionary key will throw an exception which halts execution if not caught. (similar to calling a nonexistent method or function in PHP, but since PHP doesn't have a well-thought out exception system/std. lib as Python does, you can't catch anything in that situation in PHP).
  • cheald 15y ago
    In Python, if you're expecting a potentially missing key, you can just use dict.get('key') rather than dict['key']. The equivalent in PHP would be something like: $val = array_key_exists('key', $dict) ? $dict['key'] : NULL; Being able to say "I expect a potentially nil value (and am okay with that)" via get() rather than array index is both semantically useful, and far more beautiful than the PHP equivalent.
    • Luyt 15y ago
      The more so because get() can also take a default value to return if the key is not present in the dict ;-)
    • code_duck 15y ago
      Sure, or you can catch a KeyError and do something else entirely. I'm aware of all this, just pointing out some differences to the person to whom I replied. Python's dict.get is a bit like the getOrElse found in Scala. It's quite handy and can be seen as advanced conceptually. I actually added some code like that to a recent post about PHP here: http://news.ycombinator.com/item?id=2771304 http://news.ycombinator.com/item?id=2771304
• tintin 15y ago
  I think those warnings are very helpful. They help to develop better and more secure code. Ever tried to assign a non-existing variable in another language? I think you will get a compile error. This isn't too hard: $foo = isset($_POST["foo"]) ? $_POST["foo"] : null;
• ubuntuftw 15y ago
  I think they're helpful too! Just use isset() to check whether variables exist, and you shouldn't get any errors unless you make a mistake (in which case, wouldn't it be nice to know?).