array_diff weirdness

[blinks]

I'm using the following bit of code

$diff = array_diff($pids, $pidlist); 
$diff = array_values($diff); //reindex array to remove empties
//output to $discrepancy
print_r($diff);
exit;

 

Both $pids and $pidlist contain exactly the same value; so I would have expected that value not to appear in $diff - but it is. Both $pids and $pidlist contain a few thousand values, and I've only found this one example which appears in both lists as well as $diff.

 

Can anybody shed any light?

[oni-kun]

Both $pids and $pidlist contain exactly the same value

 

Look at array_diff and you'll see the obvious answer why you get nothing. There's no differences if they are the same.

[blinks]

Sorry, I didn't explain myself very clearly. I do get a lengthy output from array_diff. The issue is that there is one particular array value from among the thousands in each array (it's an integer array)  that occurs in both $pid and $pidlist, and therefore shouldn't be in $diff, but is.

[PFMaBiSmAd]

Use var_dump() on the value in each array to see exactly what they are. You will probably find you have some white-space character as part of the value.

[blinks]

Problem solved! Although I'm still quite puzzled about one aspect of it - print_r of $pids and $pidlist was showing up the duplicated value in both arrays. The var_dump revealed it was present in one, and missing in the other. Perhaps I put the print_r in a difference location???

 

Anyway, all good now. I traced the issue back to a bug in the parent program.

 

Thanks for your help.