Help reverse my array sort comparison

Question

I have my code working perfectly how I want it to, but the problem is my code is sorting by highest value to lowest. Can you help me reverse it so that when I print out the first 10 it is actually the "10 newest" (meaning the lowest duration)?

Thanks so much

function compareStreamDurations($a, $b)
{
     if ($a["duration"] == $b["duration"]) 
     {
        return 0;
     }
     return ($a["duration"] > $b["duration"]) ? -1 : 1;
}

usort($onlineStreams, 'compareStreamDurations');

for ( $i=0; $i<10; $i++ )
{
    echo '<p>', $onlineStreams[$i]["duration"] ,'</p>';
}

The solutions posted below (reversing the sign) are NOT working. I'm doing a print_r of $onlineStreams before and after the usort function call and they are both the same.

What does your $onlineStreams array look like? Does the "duration" key exist in all array elements? Are the "duration" values numeric? — Scott McCammon
– Scott McCammon, Commented Jul 10, 2011 at 19:01
"I'm doing a print_r of $onlineStreams before and after the usort function call and they are both the same?" Does that mean that the sort isn't working in either case, or that the result of the sort is the same whether you compare with > or <? Have you tried checking the return value of usort to make sure that the sort succeeded? — Ray Baxter
– Ray Baxter, Commented Jul 11, 2011 at 2:57

Brian Geihsler · Accepted Answer · 2011-07-10 17:36:54Z

3

Just change your greater than to a less than:

return ($a["duration"] < $b["duration"]) ? -1 : 1;

answered Jul 10, 2011 at 17:36

Brian Geihsler

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1 Comment

shadowprotocol Over a year ago

This did not work when I tested using the for loop (shown above)

duffymo · Accepted Answer · 2011-07-10 17:37:39Z

0

Try reversing the greater than sign and making it a less than, like this:

function compareStreamDurations($a, $b)
{
     if ($a["duration"] == $b["duration"]) 
     {
        return 0;
     }
     return ($a["duration"] < $b["duration"]) ? -1 : 1;
}

answered Jul 10, 2011 at 17:37

duffymo

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1 Comment

shadowprotocol Over a year ago

Reversing the > to < did not rearrange properly. It is the same either way

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