Re: [PHP] Determine whether $_GET has a value

[Brent Baisley]

This is a thorny topic for some people to grasp. The way I finally 
figured it out is that there are three answers to a yes and no 
question: yes, no and no answer. Or, to put it in boolean terms 
1,0,NULL. It's that third option in a two option multiple choice 
question that throws things.

What you may be looking for is the triple equals for comparison, which 
works by "typing" the value. For example:
$testVar = NULL;
$testVar == '';  is true
$testVar === ''; is false

$testVar = 0;
$testVar == '0';  is true
$testVar === '0'; is false
$testVar == NULL; is true
$testVar === NULL; is false
Hope that helps a little.
On Jun 23, 2004, at 11:13 PM, Terence wrote:
Hi,
Say you have a querystring - index.php?myname=joe
To determine whether myname has a value I have come to the following 
conclusions / shortcomings when using one of the following:

ISSET = as long as the variable myname exists it's set, but there's no 
guarantee of a value

!EMPTY = if your name = 0 (zero) then it's considered empty, for all 
else it seems to work

STRLEN = I have found this to be the only sure way to know.
Is there any other way, or should we always use a combination of ISSET 
and STRLEN?

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Brent Baisley
Systems Architect
Landover Associates, Inc.
Search & Advisory Services for Advanced Technology Environments
p: 212.759.6400/800.759.0577
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