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Thread: comparing variable to array

  1. #1
    Join Date
    Jul 2010
    Location
    Birmingham, UK
    Posts
    67

    comparing variable to array

    can anyone explain why this is not working?

    i have a bunch of names that have been imploded and stored in my database, and when i need them again i explode the names into an array where i want to compare them to another variable. everything seems to work in terms of the imploding/exploding, but i keep on getting false negatives when i try to compare the values after exploding.

    here is a simplified example of my code:

    Code:
    $list = "name1:::name2:::name3:::name4:::name5:::name6";
    $array = explode(":::", $list);
    
    $visitor = "name3"
    
    if (!empty($visitor))
    	foreach ($array as $key => $name)
    		{if ($visitor == $name)
    			{echo $name;}
    		}
    if i just build the array and do the comparison, everything's fine. also if i simply echo the names in the "foreach" statement (without comparing to "$visitor"), i get my orignal list of names. it's just that the process of imploding/exploding to and from the database seems to screw something up - when the list comes out of my database it returns false negatives even though the values are all correct. if i build the same array on a sample page rather than calling the db (as in the above the code), the comparisons return correct repsonses. and if i echo the contents of both arrays they are perfectly identical, but the db array always returns incorrect responses.

    if there's another way to store the array without imploding/exploding that might sort things out, but i would still like to understand why this method is flawed.
    Last edited by mimewear; 09-07-2010 at 02:11 PM. Reason: adding/amending

  2. #2
    Join Date
    Oct 2007
    Posts
    374
    Maybe I missed something about the actual problem you are having. I copied your simplified code and installed it here :http://www.tecbrat.com/array_test.php It seems to work as expected.

  3. #3
    Join Date
    Jul 2010
    Location
    Birmingham, UK
    Posts
    67
    thanks for the reply tecbrat.

    yeah, i know. that's my problem. it works in the example i've written out above - it just won't work when it's coming out of my database. and when i print the two lists, they're identical. it should work or i'm going nuts (just about there).

    the actual code is a lot more inflated, but that's the crux of it. i think i must have a whitespace or some typo hiding somewhere that's causing the data to come out funny. i just needed someone else to look at to make sure i wasn't going about this the wrong way.

  4. #4
    Join Date
    Oct 2007
    Posts
    374
    When you get the data out of the database as a string, echo it with asterisks like this
    PHP Code:
    <?php echo("*$list*"); ?>
    so that you'll know if there is any white space at the ends.
    Echo your value for $visitor the same way too. Maybe there's a simpler flaw than you think. You seem to be on the right track.

  5. #5
    Join Date
    Jul 2010
    Location
    Birmingham, UK
    Posts
    67

    resolved

    thanks for that tip, though i found it in the end. the error wasn't in the list or anywhere i was expecting it might be. someone (probably me) put a whitespace in during the insert into the db, as in " $list". the nightmare in pinning down the problem was that the code is spread out across a few include files, etc. i just had a similar problem where i found that when $list was empty, ":::" was still being tacked on to the front so that there was a blank first entry in the array. and it turned out that "explode $list" was being called up needlessly in an include file somewhere. fun stuff.

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