Does isset () function do in php?

❮ PHP Variable Handling Reference

Example

Check whether a variable is empty. Also check whether the variable is set/declared:



and

will always echo 'false'. because the isset[] accepts VARIABLES as it parameters, but in this case, $foo->bar is NOT a VARIABLE. it is a VALUE returned from the __get[] method of the class Foo. thus the isset[$foo->bar] expreesion will always equal 'false'.

ayyappan dot ashok at gmail dot com

6 years ago

Return Values :
Returns TRUE if var exists and has value other than NULL, FALSE otherwise.


Could any one explain me in clarity.

mandos78 AT mail from google

14 years ago

Careful with this function "ifsetfor" by soapergem, passing by reference means that if, like the example $_GET['id'], the argument is an array index, it will be created in the original array [with a null value], thus causing posible trouble with the following code. At least in PHP 5.

For example:



will print

Array
[
]
Array
[
    [unsetindex] =>
]

Any foreach or similar will be different before and after the call.

Cuong Huy To

11 years ago

1] Note that isset[$var] doesn't distinguish the two cases when $var is undefined, or is null. Evidence is in the following code.

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