Sorting?

[Coder_10010011]

Hello. I am populating an array at the top of a php file. I am doing this so I can get all the info my script needs in one database query rather than doing multiple requests through the script.

What I want to be able to do is sort this array on any of it's entries.

	// Get the members for display into an array
	$MemberRS = mysql_query("SELECT ID, Name, DKP, Class FROM Players ...");
	if(mysql_num_rows($MemberRS))
	{
		$i=0;
		while($Member = mysql_fetch_array($Recordset, MYSQL_ASSOC))
		{
			$Members[$i]["ID"]=$Member["ID"];
			$Members[$i]["Name"]=$Member["Name"];
			$Members[$i]["Class"]=$Member["Class"];
			$Members[$i]["DKP"]=$Member["DKP"];
			$i++;
		}
	}
	mysql_free_result($MemberRS);

When I display my array contents, I may want to sort one by "ID". Then next time, I may want to sort by "Class". How difficult is it to do this?

Thanks for any help. =)

[xblue]

what exactly is "next time"?

next time the script is loaded?
on user input in some sense, like "click column caption to sort by column"?
or just further down on the same page?

[Coder_10010011]

Later in the script. I would have been doing essentially the same query as above in various places, just ordering the records differently.

So I want to make the one query up top, get all the data I will need into an array, then sort that data in different ways for later parts of the script rather than bogging the server down with repeated queries.

so will need to use the sort() function or multi_sort() I would think, but no idea how it works with an array of this type.

Yeah, you can think of it like getting a file list back into an array (filaname, size, date, attributes, etc), then later on being able to sort the array dependent on what column the user clicked.

[Coder_10010011]

Ok, almost got it figured out I think

	function cmp($a, $b)
	{
		return strcmp($a["DKP"], $b["DKP"]);
	}
	usort($Members, "cmp");

while(list($key, $value) = each($Members))
{
	echo "\$Members[$key]: ".$value["Name"].",".$value["ID"].",".$value["Class"].",".$value["DKP"]."\n";
}

The only problem with this is that There is mixed strings and numbers to be sorted. And I would like to be able to pick the desc or asc order. With the usort(), you can't specify your own arguments to the comparison function it looks like. Would like to be able to use some extra arguments like

	function cmp($a, $b, $Direction)
	{
		if($Direction == 0)
			return strcmp($a["DKP"], $b["DKP"]);
		else
			return strcmp($b["DKP"], $a["DKP"]);
	}

Or maybe this is completely the wrong way to do this. Someone out there must have an idea. =)

[Coder_10010011]

Ok, nevermind. Found some code on the php.net site that will do this for me. Going to post the solution here for anyone else that needs to do what I had to do

	function SortArray()
	{
		$arguments = func_get_args();
		$array = $arguments[0];
		$code = '';
		for($c=1; $c<count($arguments); $c+=2)
		{
			if(in_array($arguments[$c+1], array("ASC", "DESC")))
			{
				$code .= 'if($a["'.$arguments[$c].'"]!=$b["'.$arguments[$c].'"]){';
				if($arguments[$c + 1] == "ASC")
					$code .= 'return($a["'.$arguments[$c].'"]<$b["'.$arguments[$c].'"]?-1:1);}';
				else
					$code .= 'return($a["'.$arguments[$c].'"]<$b["'.$arguments[$c].'"]?1:-1);}';
			}
		}
		$code .= 'return 0;';
		$compare = create_function('$a,$b', $code);
		usort($array, $compare);
		return $array;
	}

and call it like this

	$Members = SortArray($Members, "Name", "ASC");

while(list($key, $value) = each($Members))
{
	echo "\$Members[$key]: ".$value["Name"]."\t\t".$value["ID"]."\t".$value["Class"]."\t".$value["DKP"]."\n";
}

[rehfeld]

if you wanted to use a third paramter that would not be able to be found in the array itself, i see 2 choices.

defined 2 seperate functions
cmp1() cmp2() and just decide which to use

before calling usort()

or use global variables inside your cmp function

function cmp($a, $b)
{
	if($GLOBALS['Direction'] == 0)
		return strcmp($a["DKP"], $b["DKP"]);
	else
		return strcmp($b["DKP"], $a["DKP"]);
}