PHP Function Returning Incorrect Value

Question

I'm having some real trouble with this, and I can't seem to figure out why. Please see code below. As you can see I have an array for $serverDrives set to 'C' and 'F'. I have a loop to create a new Object from a class (Drive) however when I use GetDriveLetter on the drivesArray it will always return F no matter what index I've used. I've checked that in the for loop it has both C and F, but no matter what I do I can't get it to return anything but F.

$serverDrives = ['C', 'F'];

$drivesArray = [];
for($i = 0; $i < count($serverDrives); $i++) {
    $drivesArray[$i] = new Drive($serverDrives[$i]);
}

echo $drivesArray[0]->GetDriveLetter();

Here is Drive.class.php:

<?php
class Drive {
    public $DriveLetter;

    public function Drive($driveletter) {
        global $DriveLetter;
        $DriveLetter = $driveletter;
    }

    public function GetDriveLetter() {
        global $DriveLetter;
        return $DriveLetter;
    }
}

Any ideas?

Using global for a variable is rarely a good idea. Here is leads to desaster. — arkascha
– arkascha, Commented Aug 2, 2015 at 5:38

Mike -- No longer here · Accepted Answer · 2015-08-02 05:36:23Z

2

Change your class code to this:

class Drive {
    public $DriveLetter;

    public function Drive($driveletter) {
        $this->DriveLetter = $driveletter;
    }

    public function GetDriveLetter() {
        return $this->DriveLetter;
    }
}

answered Aug 2, 2015 at 5:36

Mike -- No longer here

2,1021 gold badge25 silver badges39 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

user2416047 Over a year ago

That did the trick, but I'm curious why? What's the difference between global and using this? I assume that global is literally that, the global variable that was set last in the class? Whereas this references the Object I'm currently calling?

arkascha Over a year ago

@user2416047 I think you can answer that yourself: if you have a global variable and return the value of that in all objects of that class, why do you expect to receive different values from different objects? You always ask the value of the single, global variable.

Mike -- No longer here Over a year ago

global means make the variable thats set elsewhere available for modification in the function. $this means applicable to the class

user2416047 Over a year ago

Thanks guys! I misunderstood how global works! I'll set this as the best answer when I can.

Collectives™ on Stack Overflow

PHP Function Returning Incorrect Value

1 Answer 1

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related