[PHP] functions

[Glaanieboy]

I am a total n00b when it comes to PHP functions, therefore I ask you to help me. I have come as far as this:

function pizza_data($pizzaid){
  $search_pizza = mysql_query("SELECT * FROM pizza WHERE pizzaid=$pizzaid");
  $fetch_pizza = mysql_fetch_array($search_pizza);
  $pizza_data = $fetch_pizza['pizza'];
  return $pizza_data;
}

...
(somewhere in here, $pizzaid gets a valid value)
...

pizza_data($pizzaid);
print $pizza_data;

But that doesn't work, I get no value for $pizza_data. What magical trick should I apply to make this work? The queries are OK and when I use the function code as seperate code, it also works.

 

[Glaanieboy]

Did a bit more testing, and found some examples on http://perl.about.com/library/weekly/aa112102a.htm, like this one:

$x = 3;
print square($x);

function square($num)
{
  return $num * $num;
}

And this works flawlessly.

But when I alter the code to this (what I want), I get null results:

function square($num)
{
  $num = $num * $num;
  return $num;
}
$x = 3;
square($x);
print $num;

According to the website, it should work, but it doesn't, or am I missing something here?

 

[Geffy]

function pizza_data($pizzaid){
  $search_pizza = mysql_query("SELECT * FROM pizza WHERE pizzaid=$pizzaid");
  $fetch_pizza = mysql_fetch_array($search_pizza);
  $pizza_data = $fetch_pizza['pizza'];
  return $pizza_data;
}

...
(somewhere in here, $pizzaid gets a valid value)
...

pizza_data($pizzaid);
print $pizza_data;

ok cept for

pizza_data($pizzaid);
print $pizza_data;

try

$pizza_data = pizza_data($pizzaid);
print $pizza_data;

the $pizza_data in the pizza_data() function only has local scope to that function so when you return it you need to effectively have a place for that returned data to go, like a variable on the other side of the = from the function

btw in the second set of examples you give its returning the output to a print function

so it sends the functions result directly to be printed, you on the other hand are just calling the function and returning its result to nothingness

 

[Glaanieboy]

Clear Thanks for the explaination. I have found another (not so neat) solution for my problem though.

 

[ignipotentis]

php is not a functional language. you cannot just square x. If you want to code in the style you were using before Geffy corrected you, check out ocaml, or lisp.