the global

[runeveryday]

<?php   
function test() {   
  global $a;   
   unset($a);   
}   
   
$a = 1;   
test();   
print $a;   
?>

in the function test() i did unset($a);  but when i print $a;there is a result 1, why ?any tips would be appreciated.

[Dennis1986]

<?php
function test() {
    unset($GLOBALS['a']);
}

$a = 1;   
test();   
print $a;
?>

Destroys the global and prints nothing.

[runeveryday]

why GLOBE['a'] can't output a result,but the global can,what's difference between the two ? the more detail,the better.thank you!

[runeveryday]

who can help me? thank you!

[PFMaBiSmAd]

global and $GLOBALS should not be used in functions anyway because that breaks the general purpose nature and encapsulation that functions are designed to provide.

[runeveryday]

why not use global? if you want to use a variable which declare out of a function,but how to do it?

[KevinM1]

why not use global? if you want to use a variable which declare out of a function,but how to do it?

 

Pass it to the function via the function's argument list?

 

Example:

 

function priceWithTax($price, $salesTax)
{
   return $price + ($price * $salesTax);
}

$price = 5.00;
$tax = 0.08;

$finalPrice = priceWithTax($price, $tax);

[PFMaBiSmAd]

You pass the value pass into the function as a parameter when you call the function -

 

<?php   
function test($a) {   
   $a = NULL; 
   return $a;   
}   
   
$a = 1;   
$a = test($a);   
var_dump($a);
?>

 

The above code passes the value in as a parameter and returns the result (you cannot actually use unset in this example like the original code was doing because $a would no longer exist and could not be returned.)

 

If you actually want to unset a main program variable, I recommend just using unset() in your main code rather than making a function with it in it. Replacing a call to a built in function with a call to a user function that only contains a call to that built in function just adds unnecessary overhead to your program.