[SOLVED] compare values in an array

[vampke]

Hi guys,

 

What is "the best" way to compare the different (integer) values in an array?

Is there a function for this available or am i supposed to program it myself with for loops?

 

I found the array unique function which would remove duplicate values. Is it better to do this and check the length of the array?

 

Or is there another and better solution?

 

[kenrbnsn]

What are you trying to accomplish?

 

Ken

[vampke]

I'm trying to check if my users have entered the same value twice on a webform.

They enter 5 numbers, but the numbers need to be unique

[.josh]

dunno if there's a built in function for that (would like to know myself ) but I think you're wanting something like this?

 

<?php
// example array
$list = array('a','b','c','d','e');

$c = count($list);
for ($x = 0; $x < $c; $x++) {
   for($y = $x + 1; $y < $c; $y++) {
      if ($list[$x] == $list[$y]) {
         $duplicate = true;
      } // end if $x == $y
   } // end for $y
} // end for $x
?>

[Fadion]

As you will have an array of fixed size (5 as u stated) then array_unique() should be alright (again as you stated).

 

<?php
$array = array(1,2,3,1,5);
$unique = array_unique($array);
if(count($unique) == 5){
     echo 'alriiight';
}
?>

[vampke]

okay thanks guys, I came up with both solution already, but which one is the best, performance wise, or "any other wise"?

Is there a reason to prefer 1 over the other?

[.josh]

It depends.  Are you wanting to somehow preserve which 2 values are duplicate, as far as error message? Go with mine.  If you are simply wanting to display a generic "duplicate items not allowed" message, and your script doesn't need to preserve it? Go with guiltygear's.  I would have suggested what he did in the first place, but I guess I just assumed you wanted to somehow preserve it.

[vampke]

okay thanks,

helpfull as ever

 

[akitchin]

if you decide you want to make it a dynamic length (and thus checking against count() becomes less handy), look into using array_count_values():

 

http://us3.php.net/manual/en/function.array-count-values.php

 

combined with either a sort or a difference (i used difference), you can extract every value that was a duplicate:

 

<?php

$original = array(1, 0, 3, 3, 5, 7);

$value_counts = array_count_values($original);
$duplicates = array_keys(array_diff($value_counts, array(0)));

print_r($duplicates);

?>

 

the code's untested, but i think you'll find the difference and intersection functions for arrays is extremely handy for extracting any info you could ever want about an array.