Chris Nizzardini, Salt Lake City Utah, Web Developer Specializing in LAMP+Ajax Since 2006

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Programming

sorting a multidimensional array in php

Posted by chris on February 28th, 2008 in Programming

This will sort a multidimensional array such as this:

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Array
(
    [0] => Array
        (
            [customer_ID] => 1000
            [firstName] => Chris
            [lastName] => N
            [email] => 
            [phone] => 111-111-1111
            [joined] => 2007-07-12 12:52:38
        )
 
    [1] => Array
        (
            [customer_ID] => 1001
            [firstName] => wendy
            [lastName] => p
            [email] => 
            [phone] => 111-111-1111
            [joined] => 2007-07-11 09:21:51
        )
 
    [2] => Array
        (
            [customer_ID] => 1003
            [firstName] => Lance
            [lastName] => B
            [email] => 
            [phone] => 111-111-1111
            [joined] => 2007-07-11 09:21:51
        )
)

sortBy function

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	function sortBy($x, $y)
	{
		$reverse = $this->direction;
		$sort = $this->orderby;
		if($reverse=='true')
		{
			$numberToTimeBy = -1;
		}
		else
		{
			$numberToTimeBy = 1;
		}
		if(isset($sort))
		{
			if ( $x[$sort] == $y[$sort] )return 0;
			else if ( $x[$sort] < $y[$sort] ) return -1*$numberToTimeBy;
			else return 1*$numberToTimeBy;
		}
	}

Honestly, I don’t completely understand how this works. A friend at work sent me this function and I modified it a bit. Basically you need to set the $reverse variable to either true or false. This toggles the sorting from ascending to descending and vice-versa. Next set the $sort variable to the array index you want to sort by. The function gets called like this:

usort($this->dataArr,array('NameOfClass','sortBy'));

So $this->dataArr is the array you want to sort, NameOfClass is the name of the class you’re sorting in, and sortBy is the name of method within this class to call. Pretty interesting stuff huh.

Now if we were to use usort to sort the example array I gave in this post by first name we would do it like this:

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$this->direction = 'false';
$this->orderby = 'firstName';
usort($this->dataArr,array('MyClass','sortBy'));

The following output would be given:

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Array
(
    [0] => Array
        (
            [customer_ID] => 1000
            [firstName] => Chris
            [lastName] => N
            [email] => 
            [phone] => 111-111-1111
            [joined] => 2007-07-12 12:52:38
        )
 
    [1] => Array
        (
            [customer_ID] => 1003
            [firstName] => Lance
            [lastName] => B
            [email] => 
            [phone] => 111-111-1111
            [joined] => 2007-07-11 09:21:51
        )
 
    [2] => Array
        (
            [customer_ID] => 1001
            [firstName] => wendy
            [lastName] => p
            [email] => 
            [phone] => 111-111-1111
            [joined] => 2007-07-11 09:21:51
        )
)

I’ve been building a datagrid class and this has been a big help in sorting by column etc…

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This entry was posted on Thursday, February 28th, 2008 at 6:47 pm and is filed under Programming. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

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