Reverse array in php

Question

array(7) {
  [0]=> array(2) { ["id"]=> string(1) "9"  ["roi"]=> float(0)    }
  [1]=> array(2) { ["id"]=> string(1) "1"  ["roi"]=> float(0)    }
  [2]=> array(2) { ["id"]=> string(2) "10" ["roi"]=> float(0)    }
  [3]=> array(2) { ["id"]=> string(2) "14" ["roi"]=> float(0)    }
  [4]=> array(2) { ["id"]=> string(1) "4"  ["roi"]=> float(0)    }
  [5]=> array(2) { ["id"]=> string(1) "5"  ["roi"]=> float(141)  }
  [6]=> array(2) { ["id"]=> string(1) "6"  ["roi"]=> float(2600) }
}

I would just like to reverse this, so id 6 (with roi of 2600) comes first in the array etc.

How can I do this? array_reverse() and rsort() does not work in this case

Just going to leave this one hanging? If none helped you then post your solution and mark it accepted. — AbraCadaver
– AbraCadaver, Commented Jul 6, 2016 at 14:12

Benjamin Crouzier · Accepted Answer · 2012-04-05 12:19:48Z

24

http://php.net/manual/en/function.array-reverse.php:

$newArray = array_reverse($theArray, true);

The important part is the true parameter, which preserves the keys.

Not convinced? You can see it in action on this codepad exampole.

edited Apr 5, 2012 at 12:19

Benjamin Crouzier

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answered Apr 5, 2012 at 12:08

PeeHaa

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3 Comments

Niet the Dark Absol Over a year ago

Because they want to keep the key associativity?

PeeHaa Over a year ago

@Kolink so??? array_reverse() does that. I suggest you read the docs.

Niet the Dark Absol Over a year ago

Ah, so it does, with the extra preserve_keys parameter. My mistake.

user933791 · Accepted Answer · 2014-02-21 17:08:01Z

1

foreach($array as $arr){

  array_unshift($array, $arr); 
  array_pop($array);

}

edited Feb 21, 2014 at 17:08

answered Feb 21, 2014 at 16:58

user933791

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Comments

2 revs, 2 users 75% · Accepted Answer · 2015-12-01 02:09:57Z

1

$res = array(
    0=>array("id"=>9, "roi"=>0),
    1=>array("id"=>1,"roi"=>0),
    2=>array("id"=>10,"roi"=>0),
    3=>array("id"=>14,"roi"=>0),
    4=>array("id"=>4,"roi"=>0),
    5=>array("id"=>5,"roi"=>141),
    6=>array("id"=>6,"roi"=>2600));

$res4   =   array(); 
$count  = count($res);

for($i=$count-1;$i>=0;$i--){
    $res4[$i] =$res[$i]; 
}

print_r($res4);

edited Dec 1, 2015 at 2:09

community wiki

2 revs, 2 users 75%
railsbox

Comments

Bram · Accepted Answer · 2012-04-05 12:12:31Z

0

You can use an usort() function, like so

$arr = array('......'); // your array
usort($arr, "my_reverse_array");

function my_reverse_array($a, $b) {
    if($a['roi'] == $b['roi'])
    {
        return 0;
    }
    return ($a['roi'] < $b['roi']) ? -1 : 1;
}

This will make sure the item with the highest roi is first in the array.

answered Apr 5, 2012 at 12:12

Bram

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Comments

sumon cse-sust · Accepted Answer · 2018-05-05 08:48:31Z

0

$res = array(
    0=>array("id"=>9, "roi"=>0),
    1=>array("id"=>1,"roi"=>0),
    2=>array("id"=>10,"roi"=>0),
    3=>array("id"=>14,"roi"=>0),
    4=>array("id"=>4,"roi"=>0),
    5=>array("id"=>5,"roi"=>141),
    6=>array("id"=>6,"roi"=>2600));
    $count = count($res);

    for ($i=0, $j=$count-1; $i<=floor($count/2); $i++, $j--) {
        $temp = $res[$j];
        $res[$j] = $res[$i];
        $res[$i] = $temp;
    }
    echo '<pre>';
    print_r($res);
    echo '</pre>';

answered May 5, 2018 at 8:48

sumon cse-sust

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Comments

Prashant Pokhriyal · Accepted Answer · 2019-09-20 04:26:11Z

0

It's easy. May be use usort function of php like:

usort($arr, function($a, $b) {    
  return $b['roi'] - $a['roi'];    
});

Just swap position $a and $b that is correct.

edited Sep 20, 2019 at 4:26

Prashant Pokhriyal

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answered Sep 20, 2019 at 3:25

Ninh Mạnh Dũng

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