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Determine if a variable has been defined.

Often times I have found myself trying to determine if a variable has been set or not – especially with php which is unforgiving if you try to use a variable that hasn’t been defined.  It is for that reason that I stumbled on the isset method, which will allow you to determine if a variable has been set.  If the isset function finds that a variable is not set then it will return false.


The code below would display the following:
myvar is set
myvar2 is not set


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$myvar = “hello”;

if(isset($myvar)){ echo “myvar is set”; } else { echo “myvar is not set”;}

echo “<br>”;

if(isset($myvar2)){ echo “myvar2 is set”; } else { echo “myvar2 is not set”;}