Don't quite get Returning Values By Value script

[co.ador]

function get_global_variable_value($name)
{
return $GLOBALS[$name];
}
$num = 10;
$value = get_global_variable_value("num");
print $value;

 

The function above uses the same function name for two different purposes and getting different values only by assigning a different argument that probably will have a different value than the original function argument above.

 

the above script prints 10 how is that?

 

 

[nafetski]

Ok, pardon me if this sounds wrong but...

 

It looks like what you are doing is a horrible idea.  I'm not 100% sure what you're trying to do, but it looks like a horrible idea. 

 

Are you trying to reference a variables value by it's name? 

 

 

[KevinM1]

function get_global_variable_value($name)
{
return $GLOBALS[$name];
}
$num = 10;
$value = get_global_variable_value("num");
print $value;

 

the above script prints 10 how is that?

 

$num has a value of 10 within global scope.  $GLOBALS is an array of all global scope variables.  $GLOBALS['num'] is the same as accessing $num as though it was in scope.  As always, check the manual if you're confused about a part of the language: globals

 

With all that said, don't use the 'global' keyword or the $GLOBALS array.  It leads to poor code.

[Anti-Moronic]

function get_global_variable_value($name)
{
return $GLOBALS[$name];
}
$num = 10;
$value = get_global_variable_value("num");
print $value;

 

the above script prints 10 how is that?

 

$num has a value of 10 within global scope.  $GLOBALS is an array of all global scope variables.  $GLOBALS['num'] is the same as accessing $num as though it was in scope.  As always, check the manual if you're confused about a part of the language: globals

 

With all that said, don't use the 'global' keyword or the $GLOBALS array.  It leads to poor code.

 

Second that. I used to have a bad habit of declaring global variables when inside a function if I didn't want to have to pass those variables directly. It's just a bad idea.

 

..and writing a function to return a global variable (I would have thought) was pointless as you can get the global variable any way with $GLOBALS['num'].

[Psycho]

Edit: Nightslyr beat me to it, but I'll post this anyway:

 

function get_global_variable_value($name)
{
return $GLOBALS[$name];
}
$num = 10;
$value = get_global_variable_value("num");
print $value;

 

The function above uses the same function name for two different purposes and getting different values only by assigning a different argument that probably will have a different value than the original function argument above.

 

the above script prints 10 how is that?

 

 

This is all about variable scope. The process above is pretty strait-forward. When you set $num = 10 it is done outside of any function so it has "global" scope. When you are then IN a function that variable is not directly available. FOr example, if you defined $num inside a function it is a different instance of $num. However, you can reference global variables in a couple of ways.

 

1. Initiate the gloabl variable within the function

function name()
{
    global $num;
}

In that case $num inside the function is the same variable as $num outside the function

 

2. Using $GLOBALS keyword as in the script above. It is an associate array of all the gloabl variables. So, since $num was defined outside the function it is gloabl and you can reference it inside a function, any function, using $GLOBALS['num']

 

See the manual here: http://php.net/manual/en/reserved.variables.globals.php

 

Although I agree that function looks to be a bad idea, but is constructive for understanding the behavior

[co.ador]

I think it's just a constructive to see how that will work.

 

was not clear about.

 

To be totally clear global scope means that any variable defined outside of a function can be accessed from any part of the script right, but not from inside a function. In order to bring a variable in the global scope inside of a function would you used the global, or $Globals variables to suck it in let say....

[Psycho]

Pretty much. Look at the link I posted. The first example should give you a perfect idea of how it works.