[Resolved] Retrieving arrays from functions

MrCool

I have a function that retrieves a row from a mysql database, i want to use the array outside of the function, but the page doesn't dispay those variables. Do we have to do something to make a variable work outside of a function?

TheDefender

You have to return the variable from the function:

<?
function testmsg() {
  $testmessage = "Hello World!";
  return $testmessage;
}

testmsg();
echo $testmessage;
?>

This article is a brief tutorial on functions, but there are a bunch of other good ones. Just google something like "PHP Function tutorials" and you should find some helpful articles.

Oh, and this works with arrays as well.

suepahfly

U might want to do this:

function sql_query($query)
{
     $result = mysql_query($query);
     $array = mysql_fetch_array($result);

 return $array;
}

This should work fine

TheDefender

If you do suepahfly's suggestion, you should define the global use of the $query string in the function before calling and using it within the function (although it isn't necessary, since you aren't actually changing it's value)... so the code would be this instead:

function sql_query($query) 
{ 
     global $query;

 $result = mysql_query($query); 
 $array = mysql_fetch_array($result); 

 return $array; 
}

From an article I once read: "In PHP, a local variable is one that exists only within a function. A global variable is available anywhere in the script. Note that this is true even if a variable uses the same name in the main part of the script as well as in the function. To modify a variable from inside a function, you'll need to use the global statement."

MrCool

Something wrong with your script or my php, the world didn't say hello, it said undefined variable, shall i still look for functions or should i more look in my php config?

TheDefender

No, it's me... LOL. You have to define the global $testmessage, since you are manipulating that variable in the function. LOL... See revised code below:

<? 
function testmsg() { 
  global $testmessage;

  $testmessage = "Hello World!"; 
  return $testmessage; 
} 

testmsg(); 
echo $testmessage; 
?>

MrCool

Yep, works fine, thx every1 for the help

suepahfly

Defender your're not quite right , and also

What PHP does is making a copy of the var $query.
Let the function do somthing with $query and return this.

$query does not need to be global, since you are allready passing it to the fuction and thus making a copy of it.
in effect you have to vars called $query (one existing only with in the function)

I wrote my own sql lib using this priciple and it works fine for me. Without global variables.

You should make $query global if you define your funtion like this:


function sql_query()
{
    global $query;
    $result = mysql_query($query);
    $array = mysql_fetch_array($result);
    return $array;
}

$query = "SELECT column FROM table";
$resultSet = sql_query($query);

Now $query is a global variable available within the fuction and outside it.

Also note that you cannot do

$resultSet = sql_query("SELECT....");

if you define a function like this
Since there is no $query.

ps:
*nm the ps

devinemke

another option is to place variables directly into the GLOBAL array. these two examples both do the same thing: create a global variable called "var" that contains "HELLO WORLD"

// example #1
function upper($string)
{
	$string = strtoupper($string);
	return $string;
}
$var = upper('hello world');


// example #2
function upper($string)
{
	$string = strtoupper($string);
	$GLOBALS['var'] = $string;
}
upper('hello world');

TheDefender

I stand upgraded. Thanks for the lesson and info guys. That's the best part of this site... the "learning something new every day" thing.

Sincerely,
TheDefender v2.4.1