Complex multiple condition sort routine 1

[Zhris]

Hi,

I'm trying to sort data in a particular way:
- Primarily by the users choice.
- Secondarily by "coordinates" (keys 'X' or 'Y' or 'Z').
However, when the user first visits the webpage, because they haven't yet made a choice on how to sort the data, it should be sorted by default by the secondary method only.

I am struggling to achieve the above task because the first condition of the sort routine would be "dynamic" (0 arguements (no user input), 1 arguement (user input), or possibly 3 arguements (default x, y, z)), if you understand what I mean.

Here is some example data:

my $data = [
	{
		'X' => "1",
		'Y' => "1",
		'Z' => "12",
		'Username' => "Chris",
		'ID' => "1672"
	},
	{
		'X' => "1",
		'Y' => "1",
		'Z' => "14",
		'Username' => "Peter",
		'ID' => "849"
	},
	{
		'X' => "1",
		'Y' => "2",
		'Z' => "2",
		'Username' => "Laura",
		'ID' => "801"
	},
	{
		'X' => "4",
		'Y' => "6",
		'Z' => "8",
		'Username' => "Emily",
		'ID' => "4690"
	},
	{
		'X' => "2",
		'Y' => "9",
		'Z' => "12",
		'Username' => "Daniel",
		'ID' => "7012"
	},
	{
		'X' => "1",
		'Y' => "1",
		'Z' => "4",
		'Username' => "Chris",
		'ID' => "1674"
	}
];

And here is my initial attempt at sorting it, pretending there is user input:

my %sortroutines = (
	'X' => sub { $_[0] <=> $_[1] },
	'Y' => sub { $_[0] <=> $_[1] },
	'Z' => sub { $_[0] <=> $_[1] },
	'Username' => sub { $_[0] cmp $_[1] },
	'ID' => sub { $_[0] <=> $_[1] }
);

my $sortby = 'Username';

foreach my $row (sort { (     $sortroutines{$sortby}->($a->{$sortby}, $b->{$sortby})     ) || (     $sortroutines{'X'}->($a->{'X'}, $b->{'X'}) || $sortroutines{'Y'}->($a->{'Y'}, $b->{'Y'}) || $sortroutines{'Z'}->($a->{'Z'}, $b->{'Z'})     ) } @$data) {
	foreach my $cell (sort keys %$row) {
		print "$$row{$cell}<br />";
	}
	print "<br />";
}

And my most recent attempt at achieving my overall task (messy):

my %sortroutines = ();
%sortroutines = (
	'Initial' => sub { $sortroutines{'X'}->($_[0], $_[1], 'X') || $sortroutines{'Y'}->($_[0], $_[1], 'Y') || $sortroutines{'Z'}->($_[0], $_[1], 'Z') },
	'X' => sub { $_[0]->{$_[2]} <=> $_[1]->{$_[2]} },
	'Y' => sub { $_[0]->{$_[2]} <=> $_[1]->{$_[2]} },
	'Z' => sub { $_[0]->{$_[2]} <=> $_[1]->{$_[2]} },
	'Username' => sub { $_[0]->{$_[2]} cmp $_[1]->{$_[2]} },
	'ID' => sub { $_[0]->{$_[2]} <=> $_[1]->{$_[2]} }
);

my $sortby = param('sortby') || 'Initial';

foreach my $row (sort { (     $sortroutines{$sortby}->($a, $b, $sortby)     ) || (     $sortroutines{'X'}->($a, $b, $sortby) || $sortroutines{'Y'}->($a, $b, $sortby) || $sortroutines{'Z'}->($a, $b, $sortby)     ) } @$data) {
	foreach my $cell (sort keys %$row) {
		print "$$row{$cell}<br />";
	}
	print "<br />";
}

My 2nd attempt doesn't work correctly. My question is, how can I ignore the first condition of the sort routine if it isn't needed? If I haven't made myself clear enough, please ask for further details.

Thank you very much in advance for helping.

Chris

 

[prex1]

Simply add the line
[tt]'Initial'=>sub{0},[/tt]
to your [tt]%sortroutines[/tt] and make
[tt]$sortby='Initial';[/tt]
the default value.

Franco

http://www.xcalcs.com

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[Zhris]

Thank you Franco,

I was unaware that it would be as simple as that, and would have never of thought to use 0. It worked perfectly.

Chris