Sort array by two specifics values in PHP

Question

The folks have already showed me how to sort an array by a specific value using usort and a fallback function in PHP.

What if this specifc value doesn't exist and we have to use two values? in the example bellow the values [4] and [5]... In other words, I want to do this: order all objects numericaly by the fith value of each object from the highest to the lowest, and addicionally, for those objects that have the fifht value is empty (in the examplem '-'), order them by the fourth value.

Array(

 [0] => Array(
  [0] => links-patrocinados
  [1] => adwords
  [2] => 0,5
  [3] => R$92,34
  [4] => 823000
  [5] => 49500
 )
 [1] => Array(
  [0] => adwords
  [1] => google adwords como funciona
  [2] => 0,38
  [3] => R$0,20
  [4] => 480
  [5] => 480
 )
 [2] => Array(
  [0] => links-patrocinados
  [1] => adword
  [2] => 0,39
  [3] => R$58,77
  [4] => 49500
  [5] => 2900
 )
 [3] => Array(
     [0] => agencia
     [1] => agencias viagens espanholas
     [2] => -
     [3] => R$0,20
     [4] => 58
     [5] => -
 )
 [4] => Array(
     [0] => agencia
     [1] => era agencia imobiliaria
     [2] => -
     [3] => R$0,20
     [4] => 73
     [5] => -
 )

)

What do you mean when you say "sort this array by the value[5]"? — Kyle Wild
– Kyle Wild, Commented Jan 16, 2011 at 0:39
Looks like the code you linked to should be what you want. What isn't working? What does your code look like? — jasonbar
– jasonbar, Commented Jan 16, 2011 at 0:40
I ment sorting the multidimentional array by numerical order taking by reference the fifth value of the array. Just like you ("dorkitude") did in your answer bellow. Now the challenge changed a bit, for, some object have the fifth value empty, so how do I order them taking in consideration the fourth value? — Roger
– Roger, Commented Jan 16, 2011 at 10:09
what if one variable has a 5th value, and one doesn't? How do you want to place them? — Dogbert
– Dogbert, Commented Jan 16, 2011 at 10:20

Kyle Wild · Accepted Answer · 2011-01-16 00:40:50Z

5

// $myArray = your array of associative arrays, above
function compare($x, $y)
{
    if ( $x[5] == $y[5] ) {
        return 0;
    }
    else if ( $x[5] < $y[5] ) {
        return -1;
    }
    else {
        return 1;
    } 
}

usort($myArray, 'compare');

answered Jan 16, 2011 at 0:40

Kyle Wild

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3 Comments

BoltClock Over a year ago

usort($myArray, function($x, $y) { return $x[5] - $y[5]; });

BoltClock Over a year ago

Yeah, otherwise function compare($x, $y) { return $x[5] - $y[5]; }

Roger Over a year ago

Thanks everybody. I had already used the same solution but I think it was too late at night I din't understand it worked :-) Well, now I complicating things a bit more, please, take a second look at the problem, will you?

salathe · Accepted Answer · 2011-01-16 12:27:16Z

2

You just need to change your callback function to return negative, zero or positive numbers depending on the values present (or not) in the two items being compared at any one time; just as you would when comparing a single array index in both items.

function callback($a, $b) {
    // Both have [5] so sort by that
    if ($a[5] !== '-' && $b[5] !== '-')
        return $b[5] - $a[5];

    // Neither have [5] so sort by [4]
    if ($a[5] === '-' && $b[5] === '-')
        return $b[4] - $a[4];

    // One has a [5] value
    if ($a[5] === '-')
        return 1;
    else
        return -1;
}
uasort($array, 'callback');
print_r($array);

In this particular case, the above callback could be whittled down to something like:

function callback($a, $b) {
    // Neither have [5] so sort by [4]
    if ($a[5] === '-' && $b[5] === '-')
        return $b[4] - $a[4];

    // One, or both, has a [5] value
    return $b[5] - $a[5];
}

answered Jan 16, 2011 at 12:27

salathe

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1 Comment

Roger Over a year ago

Thank you, Salathe, it worked just fine. And congratullations for you tiny code.

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