CODEWITHSUNDEEP
phpclassoop
John T
John T

Reputation: 1078

PHP classes - is it preferable to use normal variables instead of properties?

For my latest website I’ve been trying to use classes. Mainly to teach myself more about OOP and learn through experience.

Whenever I needed a ‘variable’ within my class I created a property, for instance:

class someClass
{

var $valueToUseHere; // Only used internally - can I just use a variable?

    public function doStuff()
    {
        $this->valueToUseHere = 60;
    // Do more stuff here...
    }

}

It is only now when I’ve been looking more into the code and trying to do some optimisation that I’ve noticed that my functions and classes are passing around some large objects. A lot of that bulk could be stripped away if I made all the properties that are only used inside the class into normal variables.

Are properties only used for variables that are needed outside the class and is it then acceptable to just use ‘normal’ variables within the class itself ?

Sorry if this question illustrates a lack of understanding on the subject. Unfortunately, this is where my learning is up to at this point. I’ve done some searching around “class properties vs variables” etc but not found a comprehensive answer to this.

Many thanks

Upvotes: 4

Views: 2220

Answers (3)

Mojtaba Rezaeian
Mojtaba Rezaeian

Reputation: 8736

In brief you may prefer to use:

Properties: When you want to have control about get and set values
Variables: When you want to set or use a variable as its nature

That depends on your needs. If you are going to simply hold a value in a variable it's the best to keep it's simplicity and not define functions for setting or getting it's value. But sometimes you may need to have more controls on a variable in your class. For example you have defined an integer variable and you want it's values to be always between 10 and 1000 and also it should not be in 100,200,300,..,900. So here there is a good reason to set your variable access to private and create a public function to check what is required before accepting new input; Or in another example you may want to call another function or change another depended variable in your class exactly after this variable changed(for example this variable is defining width of a rectangle in graphical output so you need to call related graphical functions exactly after changing this variable); And if you want to make a variable read-only or write-only always you can define properties for controlling the type of variable behaviour.

Upvotes: 2

ChristianM
ChristianM

Reputation: 1823

Actually class properties are variables as well. Basically you have three options:

Global variable, available everywhere, but not recommended because all parts of your code may depend on such a varialbe, changes can easily break stuff everywhere.

Class property (Note: you should define a visibility - public/protected/private) these properties are bound to the object instance and should be used for any state that the object needs to keep for further processing. Usually those might be used in more than one metohd of your class.

Variables inside a method like just

public function doStuff()
{
    $valueToUseHere = 60;
    // Do more stuff here...
}

The variable is just available inside the method and is thrown away at the end of the method execution.

Upvotes: 3

deceze
deceze

Reputation: 522015

It's somewhat vague what you're asking, but if valueToUseHere is not used outside of doStuff, then don't make it a property!

class someClass {

    public function doStuff() {
        $valueToUseHere = 60;
        // Do more stuff here...
    }

}

If there's no reason to share that value with other methods of the class or with the outside world, then there's no reason to clutter up your object with all sorts of properties. Not only may this cause tricky bugs with preserved state, it also forces you to be unnecessarily careful with your variable names across all object methods.

Upvotes: 6

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