Check whether class variable has been defined

PHP
1

If I declare class variables but don’t assign values, can I check whether those variables have been defined?

eg


class myclass
{
	public $myVar;
	
	function myFunction()
	{
		var_dump(isset($this->myVar));
	}
}

Or something like that. It seems that the variable doesn’t exist unless I assign a value ie


class myclass
{
	public $myVar = "nothing";
	
	function myFunction()
	{
		var_dump(isset($this->myVar));
	}
}

Any ideas?

2

isset returns 1 if the variable is defined and is not null.

3

isset determines if a variable is set and is not NULL. Where my class variable is declared but not assigned a value it appears to be null, hence, isset is still false, so that’s not giving me the value I want.

4

Sound to me you’re looking for [fphp]property_exists[/fphp] :slight_smile:

5

Bang on! Thanks a lot, that did the trick!

6

OK Here’s another one: How do check the visibility of the variables?
I’ve searched for this, I promise :slight_smile: but come up with nothing!

7

I don’t think there are methods for that, but there’s always reflection :slight_smile:
Some scary stuff going on in there …

8

Here there be dragons! Yeah, I think I’ll give that one a miss and stick with propert_exists. Cheers!

9

Generally you might want to put that property_exists as a method of the class, so you could use something like:

if($SomeObject->myVarIsSet()){

Though generally things are given a default value in the constructor - what I’d recommend there is setting it to false by default:

if($SomeObject->myVar !== false){