Checking for empty values in array

[markkanning]

Hey all,

I'm looking for a quick, boolean-style method of checking for empty values in an array without looping through it first. Is there something like:

$newarray = array('first' => "", 'second' => 2);
if (empty_value($newarray)) {
   return false;
}

 

I made up the "empty_value()" thing. But essentially I'd like to check for empty values before deciding to loop through the array.

 

Any ideas?

 

Mark

[per1os]

www.php.net/empty

www.php.net/isset

[utexas_pjm]

There is no way to tell if any 1 element of an array is empty in constant time (O(1)).  The best you can do is O(n) where n is the length of the array.  You can of course define a function that traverses the array and returns true as soon as it finds a null value.

 

<?php
$newarray = array('first' => "", 'second' => 2);
if (empty_value($newarray)) {
   return false;
}

function empty_value($arr)
{
  foreach($arr as $val){
   if ($val === null)
     return true;
  }
  return false;
}
?>

 

Best,

 

Patrick

[markkanning]

Thanks, Patrick. I was figuring that sort of thing might be the only solution.

 

Mark

[Barand]

Hmm,

 

Your first "return false" is invalid, not in a function.

 

And empty string is not a null value

 

try

<?php
$newarray = array('first' => "", 'second' => 2);
if (empty_value($newarray)) {
   echo "Empty value found";
}

function empty_value($arr)
{
  foreach($arr as $val){
   if (!$val)
     return true;
  }
  return false;
}
?>

[utexas_pjm]

Your first "return false" is invalid, not in a function.

 

D'oh.  Just copied and pasted from above.

 

And empty string is not a null value

 

You're right... I used === null because of a case like this:

 

<?php
array("foo" => false, "bar" => 0, "baz" => "");
// These would all return true in "if(!$val)", probably not the expected result (thanks PHP!).
?>

 

Maybe we should have done something like this:

 

<?php
$newarray = array('first' => "", 'second' => 2);
if (empty_value($newarray)) {
   echo "Empty value found";
}

function empty_value($arr)
{
  foreach($arr as $val){
   if ($val === "" || $val === null)
     return true;
  }
  return false;
}
?>

 

Patrick

[Barand]

I'll go along with that