Does array_multisort mantain key association for you?

**spybreak** · Mar 30, 2004 13:38

Does array_multisort mantain key association for you?

The manual says:

array_multisort() can be used to sort several arrays at once or a multi-dimensional array according by one of more dimensions. It maintains key association when sorting.

It doesn't for me. They keys are lost and it renumbers them from 0 to n. I have PHP 4.3.4

**coo_t2** · Mar 30, 2004 15:52

If you want, you can post a simple example of your code, and I'll try it out and see what it does for me.

--ed

**spybreak** · Mar 30, 2004 17:26

PHP Code:


<?

//names array. keys are user id's

$names[5]  = 'Peter';

$names[7]  = 'Jim';

$names[11] = 'Martin';

$names[33] = 'John';

$names[34] = 'Robert';



//age array. keys are user id's

$age[5]    = 15;

$age[7]    = 19;

$age[11]   = 54;

$age[33]   = 29;

$age[34]   = 17;



//sort names array by ages

array_multisort($age, $names);



var_dump($names);



// returns the following for me

//

// array

//   0 => 'Peter'     (age 15) <-- i just put the ages here                   

//   1 => 'Robert'    (age 17)     to demonstrate that array_multisort        

//   2 => 'Jim'       (age 19)     sorted everything correctly (expect that it

//   3 => 'John'      (age 29)     didn't mantain key association)

//   4 => 'Martin'    (age 54) 

//

//

// _should_ return

//

// array

//   5  => 'Peter'    (age 15)

//   34 => 'Robert'   (age 17)

//   7  => 'Jim'      (age 19)

//   33 => 'John'     (age 29)

//   11 => 'Martin'   (age 54)





?>

thanks! I'm curious on what it outputs for you

**spybreak** · Mar 30, 2004 17:31

ok just read this at the php.net array_multisort comments section

It should be noted that whilst the manuel says:
"It[array_multisort] maintains key association when sorting".
This is only Partially true.

It will maintain string keys and associates them properly.
However if you are using numeric keys, it will reset them to 0.