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Make the loop and variable variables into a function

Posted: Fri Aug 20, 2010 8:14 am
by lauthiamkok
Hi,

How can I make the code below into a function?

Code: Select all

# split the string by string on boundaries formed by the string delimiter will split the value into an array like the example below,
# Array
# (
#     [0] => pg_cat_id=1
#     [1] => tmp_id=4
#     [2] => parent_id=2
# )
$array_parent = explode("&", $string);
//print_r($array_parent);

# now loop the array.
for($i = 0; $i < count($array_parent); $i++)
{	
	# split the array into smaller arrays with the string delimiter, like the example below,
	# 	Array
	#	(
	#		[0] => pg_cat_id
	#		[1] => 1
	#	)
	#	Array
	#	(
	#		[0] => tmp_id
	#		[1] => 4
	#	)
	#	Array
	#	(
	#		[0] => parent_id
	#		[1] => 2
	#	)
	$array_child = explode("=", $array_parent[$i]);
	//print_r($array_child);
	
	# loop each of the array.
	for($a = 0; $a < count($array_child); $a++)
	{	
		# get the first value in each array and store it in a variable.
		$v = $array_child[0];
		
		# make the variable variable (sometimes it is convenient to be able to have variable variable names. 
		# that is, a variable name which can be set and used dynamically. a variable variable takes the value 
		# of a variable and treats that as the name of a variable). 
		${$v} = $array_child[1];
	}
}
so that I can call the function whenever I need it, such as below,

Code: Select all

$string = 'pg_cat_id=1&tmp_id=4&parent_id=2';

echo stringToVarVars($string);

echo $tmp_id; // I will get 4 as the restult.

Many thanks,
Lau

Re: Make the loop and variable variables into a function

Posted: Fri Aug 20, 2010 10:30 am
by AbraCadaver
PHP has already done this for you:

Code: Select all

$string = 'pg_cat_id=1&tmp_id=4&parent_id=2';
parse_str($string);
echo $tmp_id;

Re: Make the loop and variable variables into a function

Posted: Fri Aug 20, 2010 10:50 am
by lauthiamkok
AbraCadaver wrote:PHP has already done this for you:

Code: Select all

$string = 'pg_cat_id=1&tmp_id=4&parent_id=2';
parse_str($string);
echo $tmp_id;
thanks alot! love PHP!! :D

Re: Make the loop and variable variables into a function

Posted: Fri Aug 20, 2010 10:58 am
by shawngoldw
Academically speaking, if you wanted to create a function to do this, how would you? Wouldn't the variables be out of scope?


Shawn

Re: Make the loop and variable variables into a function

Posted: Fri Aug 20, 2010 11:27 am
by AbraCadaver
Some ways:

The function could return an associative array of 'var'=>'val':

Code: Select all

function stringToVarVars($string) {
   // build $vars array
   return $vars;
}
extract(stringToVarVars($string));
//or
$vars = stringToVarVars($string);
extract($vars);
Or you could pass a var by reference and modify it as an associative array in the function:

Code: Select all

function stringToVarVars($string, &$vars) {
   // build $vars array
}
stringToVarVars($string, $vars);
extract($vars);

Re: Make the loop and variable variables into a function

Posted: Fri Aug 20, 2010 11:39 am
by AbraCadaver
So those two will work in global scope or inside another function. This one will only work in global scope:

Code: Select all

function stringToVarVars($string) {
	foreach(explode('&', $string) as $assignment) {
		list($var, $val) = explode('=', $assignment);
		$GLOBALS[$var] = $val;
	}
}

Re: Make the loop and variable variables into a function

Posted: Fri Aug 20, 2010 12:44 pm
by shawngoldw
But those still wouldn't work quite like parse_str since you would have to call another function afterwards to get the same result. I think the $GLOBALS method is the closest, but still not quite the same

Shawn

Re: Make the loop and variable variables into a function

Posted: Fri Aug 20, 2010 3:19 pm
by AbraCadaver
shawngoldw wrote:But those still wouldn't work quite like parse_str since you would have to call another function afterwards to get the same result. I think the $GLOBALS method is the closest, but still not quite the same

Shawn
Yep, that's why I use parse_str() :)