| Re: Parameter passing question [message #173549 is a reply to message #173542] |
Mon, 18 April 2011 18:54   |
Denis McMahon
Messages: 634
Registered: September 2010
Karma:
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Senior Member |
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On Mon, 18 Apr 2011 14:20:00 -0400, Chuck Lavin wrote:
> "Denis McMahon" <denis(dot)m(dot)f(dot)mcmahon(at)gmail(dot)com> wrote in message
> news:4dac7807$0$23634$bed64819(at)gradwell(dot)net...
>> On Mon, 18 Apr 2011 13:03:24 -0400, Chuck Lavin wrote:
>>
>>> How do I tell these three passed parameters apart (PHP 5)?
>>
>>> http://www.somewhere.com?param=value // param has been set to
>>> 'value' http://www.somewhere.com?param= // param has been set to
>>> empty (or null)
>>> http://www.somewhere.com // param has not been set at all
>>
>> This smells like it might be a homework question, or someone doing a
>> w3schools online certification, but I'll bite.
>>
>> Have you tried something like the following:
>>
>> <?php
>> if (isset($_GET['x'])) {
>> if ($_GET['x'] == null) {
>> // it's null
>> } else {
>> // it has data
>> }
>> } else {
>> // it's not defined
>> }
>> ?>
>>
>> If you have tried it, did it do what you want, and if not how did it
>> fail to do so[1]?
>>
>> If you haven't tried it, what have you tried so far?
>>
>> If you can't figure out what to use for x, please ask your teacher to
>> revise passing parameters with you again.
>>
>> Rgds
>>
>> Denis McMahon
>>
>> [1] I don't think it quite does what you want, but I also think the
>> change that needs to be made is trivial and you should be able to
>> deduce it yourself.
This is a newsgroup. Reply goes at the bottom.
> This is not a homework assignment. I'm working on a live remote server
> that I'd rather not be playing around with.
>
> According to the PHP doc page for isset(), isset() can't tell the
> difference between a variable that's not set and a variable that's
> empty.
>
> I need to move passed parameters into session variables:
>
> 1) If a parameter is passed with a value, set the session variable with
> that value;
>
> 2) If a parameter is passed with an empty value, get rid of that session
> variable;
>
> 3) If a parameter is not passed at all (not referenced in the URL),
> don't touch the session variable.
>
> And right now I can't tell the difference between a parameter being
> passed empty and no parameter being passed at all.
Everything in the $_GET array is a string.
The following should work:
<?php
if (isset($_GET['x'])) {
if ($_GET['x'] === "") {
// an empty string
} else {
// a non empty string
}
} else {
// not defined
}
?>
Rgds
Denis McMahon
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