Ok stupid question.. but its driving me crazy... more and more scripts I pull apart I have been seeing something like this..

$this->info = array();

And for some reason... $this-> part is usually highlighted...which is what is throwing me off... I have tried looking it up.. but I cant find anything.... what is it doing?

As per http://

php

 

.net

 /class

So, in the context of your post "info" is a variable (in this case an array) which is a member of a class (object) which $this points to (NOTE: it is an internal pointer, it cannot be used from outside the class scope). Here's an example;



[edit]Removed moronicness in code.[/edit]

HTH,
td

your not an idiot, i had the same exact question about a week ago for perk.
Another way to explain it is that it is DOT notation.

$this->info = array();

is the same as:

$this.info = array();

<>info is the method or property
<>this is the object

though i am not sure if you are setting array or setting $this?

In this case NBs, you are setting a null array pointer to the $this->info member property/reference/variable/whatever you want to call it.

In

PHP

  the garbage collection and variable construction is automatic. So the reason you do this is if you will need to call a function that REQUIRES an array to be created first (like implode()) or if you are cleaning up memory from a previous array. For example, if you had 10K elements in $this->info and wanted to throw them away and free the memory, but still keep info as an array, then by saying $this->info = array() is an easy way to effect that.

Another reason for this notation is that you can both construct and populate the array in one pass. Consider:

$this->info = array(0=>'Hello', 1=>'World');

would create the array info in the current class ($this) and set element [ 0 ] to 'Hello' and [ 1 ] to 'World' . You can do associatives like this as well:

$this->info = array('key1'=>'avalue', 'anotherkey'=>'yet Another Value!');

/p

oh i get it.

its a constructor. not just a Object.Method call.

$this is a variable initially not a class correct?
info doesnt exists until it is set = the array that you make. array() is just an empty array.
info is more like a "sub variable" correct?
im guessing you can do
$this->somerandomthingy = array() as well right? if so, i get it.

@ constructor - precisely. Arrays are just a bit different than primitives and as such, you create them with that function. They'll be auto-created if you were to do something like this:

$myArr[] = 'Hello';
$myArr[] = 'World'

... so that the index reference is auto-incremented. Using array() is just more formal and tells

PHP

  what your intentions are very clearly.

@ $this - right on again. the $this C++ and Delphi equivalent is self. As you know, you'll code using the word $this in the class definition, but the $this context does not exist until an object has been created against that class... and then the $this is a reference to itself. $this can never be used outside of a class definition - it is a reserved word.

@ info: consider the following -

class myClass
{
private $anInt;
protected $anotherInt;
public $yetAnotherInt;
var $thisVarDefaultsToPublicInt;

function __construct()
{
$this->anInt = 0;
$this->anotherInt = 1;
$this->yetAnotherInt = 2;
$this->thisVarDefaultsToPublicInt=32767;
}
}

... and now in the normal flow of code...
$myObj = new myClass();
print $myObj->thisVarDefaultsToPublicInt; // prints 32767
print $myObj->yetAnotherInt; // prints 2
print $myObj->anotherInt;
print $myObj->anInt; // Both of these fail because of their visibility in the class

info in the previous examples is just a property or member or whatever their calling a class variable these days.

QQ: Are you a strong OO guy or is this new stuff?

/p

Ahhh OOP & classes...  I haven't gotten that far yet... I head that stuff wasnt for beginners to

php

  and that it was a matter of personal preference...  I personally prefer something easy..lol...  I want to spend more time <>scheming planning...than coding

But thanks for finally explaining what that is...I can sleep now 

ah ok. i get it. duh.
info is just a property that was declared in some class. just happens the assignment is inside that class, so $this is the shorthand so you dont have to be reliant upon the class name changing. got it. its a standard oop model.

Being picky here perk but I'm pretty sure the C++ equivalent of "$this->" is "this->" not "self->" isn't it?

Cheers,
td

You may well be right TD - It's been since the mid 90s that I've even touched C++ - that was Borland 3.1 and it was great, but I am pretty certain that I've forgotten anything pertinent... at least I was clear enough so that you could debug me 

Yes this-> is correct
Does

PHP

  have dot notation? if so it may carry the same benefits of dot notation in C++ in that its faster [one less lookup]
However I doubt it