| Re: uasort strange problem [message #173430 is a reply to message #173429] |
Wed, 13 April 2011 01:29   |
Jerry Stuckle
Messages: 2598
Registered: September 2010
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Senior Member |
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On 4/12/2011 6:38 PM, Peter wrote:
> Hi all,
>
> I currently have a list of products stored in a multi-dimensional array
> which contains, amongst other fields, the product's name, heading
> 'name', and the product's price, heading 'price' and I want to be able
> to sort the array by name ascending/descending and price
> ascending/descending.
>
> The array is originally created from a mysql database using various
> tables and so I have not been able to create a simple, mysql query that
> allows me to return the data already sorted. There are various reasons
> for this which I don't wish to go into here, being a php forum.
>
> So I found out about the uasort function, plus a small routine that
> seemed to be just what I was looking for to allow me to sort on either
> 'name' or 'price' ascending. I then discovered the array_reverse
> function which I thought would allow me to reverse the array to allow me
> to have 'name' or 'price' descending options.
>
> At least that's what I thought, but I'm new to both functions and so I
> might be missing something obvious and so hope that someone here can
> point out my mistakes.
>
> Here's the problem. If I just compare on either 'name' or 'price'
> ascending the array remains unsorted. If I compare on either 'name' or
> 'price' ascending and then use the array_reverse function it works like
> a charm and the array is perfectly sorted in descending order. So what
> I'm not getting is this, how can an array that remains unsorted when
> using either of my compare functions, suddenly become sorted when
> reversed?
>
> Hope someone here can explain.
>
> Here is the php that I am using to sort the array:
>
> switch($searchtype){
> case '1':
> uasort($array, 'compare_nameAsc'); // sort on name ascending
> break;
>
> case '2':
> uasort($array, 'compare_nameAsc'); // sort on name ascending
> $array = array_reverse($array); // reverse the sort order
> break;
>
> case '3':
> uasort($array, 'compare_priceAsc'); // sort on price ascending
> break;
>
> case '4':
> uasort($array3, 'compare_priceAsc'); // sort on price ascending
> $array = array_reverse($array); // reverse the sort order
> break;
> }
>
> And here are the 2 functions:
>
> function compare_nameAsc($a, $b)
> {
> return strnatcmp($a['name'], $b['name']);
> }
> function compare_priceAsc($a, $b)
> {
> return strnatcmp($a['price'], $b['price']);
> }
How are you displaying the items? uasort() maintains the key/value
association, but array_reverse() does not by default.
P.S. In general, it's better to let the database do the sorting. Maybe
you would like to follow up on that end in comp.databases.mysql.
--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex(at)attglobal(dot)net
==================
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