[RESOLVED] Quick way to check for empty associative array?

Joseph_Sliker

Hi;

Is there a quick way to see if an associative array is completely empty (ie. user filled in no boxes or fields, but hit the submit button anyway.)

ie. say the array print_r is like this:

Array (
[740] => Array ( [ANSWER] => )
[741] => Array ( [ANSWER] => )
[742] => Array ( [ANSWER] => )
[743] => Array ( [ANSWER] => )
[744] => Array ( [ANSWER] => )
[745] => Array ( [ANSWER] => )
[747] => Array ( [ANSWER] => )
[749] => Array ( [ANSWER] => )
[750] => Array ( [ANSWER] => )
[751] => Array ( [ANSWER] => )
)

(the first key is a question item id number. Answers may sometimes be numeric or text strings...I just want a quick check to see that the entire array was left empty.)

array_count_values does not quite do the trick.

I just want something that will quickly return a "0" or something like that.

Any ideas?

Thanks.

laserlight

I can see a simple recursive solution, but it takes time proportional to the number of subarrays and elements:

function isEmptyArray($value) {
    if (is_array($value)) {
        foreach ($value as $element) {
            if (!isEmptyArray($element)) {
                return false;
            }
        }
        return true;
    } else {
        return empty($value);
    }
}

NogDog

I came up with the following approach using array_walk_recursive(). Can't say I'm entirely happy with it, as I feel there should be a more elegant way to do it that does not include the need for a global variable; but at least it works. 🙂

function notEmpty($val, $key)
{
   global $notEmptyResult;
   if(trim($val) !== '')
   {
      $notEmptyResult = TRUE;
   }  

}
$notEmptyResult = FALSE;
array_walk_recursive($inputArray, 'notEmpty');
if($notEmptyResult)
{
   echo "It has some data";
}
else
{
   echo "It is empty.";
}

NogDog

Update: got around the globals issue.

function notEmpty($val, $key, &$out)
{
   if(trim($val) !== '')
   {
      $out = TRUE;
   }  

}
$notEmptyResult = FALSE;
// need to use & for 3rd arg here, as well as in callback function arg
array_walk_recursive($inputArray, 'notEmpty', &$notEmptyResult);
if($notEmptyResult)
{
   echo "It has some data";
}
else
{
   echo "It is empty.";
}

laserlight

If array_walk_recursive() took its third argument by reference, or if we used call time pass by reference, the global variable could be avoided. Unfortunately, call time pass by reference has been deprecated, and array_walk_recursive() takes its third argument by value.

Joseph_Sliker

Thanks for the suggestions...thought there might be something easier than writing some sort of recursive function, but with your suggestions I cobbled together something that works:

ECHO "EMPTY DATA SHEET CHECK.<BR>";
foreach($_SESSION['roomspicked'] as $sheet=>$number) 
{ECHO "DATA SHEET: $sheet<BR>";
$itemcount=count(array_keys($DATA[$sheet]));

foreach ($DATA[$sheet] as $item=>$resp)
if ($resp[ANSWER]=='') {$answ[$sheet][]='(blank)';} else {$answ[$sheet][]="$resp[ANSWER]";} 

$TEMP=array_count_values($answ[$sheet]);

$temp2=$TEMP['(blank)'];
ECHO "$itemcount items vs $temp2 blank answers:  ";
if ($temp2 < $itemcount) {ECHO "Save record.";} else {ECHO "Skip record (do not save).";}
ECHO "<BR>";
}

(If you want to know the background...the sending form will have multiple columns (the "sheet" dimension) for rating several classrooms on various dimensions all at once. And if, for example, one or more of the rooms were not rated, there would be no need to save the record for those rooms. The itemcount is the number of items on which each room can be rated. If the number of blanks equals the number of items...no need to save the record because no data was provided.)

The output looks like this:

EMPTY DATA SHEET CHECK.
DATA SHEET: 1
60 items vs 60 blank answers: Skip record (do not save).
DATA SHEET: 2
60 items vs 59 blank answers: Save record.
DATA SHEET: 3
60 items vs 58 blank answers: Save record.

This will actually be used to tell the script whether or not to do the mysql insert.

Thanks a bunch.