[SOLVED] Array Help

[onlyican]

Hey people

I am building a Seating plan editor.

Ignore the Keys as it is not important for this question.

I have an Array such as

[J/1] => J1 
[J/2] => J2 
[J/3] => J3 
[J/4] => J1 
[J/5] => J3 
[J/6] => J6 
[J/7] => J7);

Warning: Original array could be up to 1000 values.

 

What I need to do is get an array of all of the values which are Duplicated.

For example, the above, I would like an array of

Array ([0] => "J1", [1] => "J3");

As there are more than 1 entries for J1 and J3 as vaulues, (NOT Keys, Ignore Keys, just Values).

 

What is the best way of doing this, Remember that the array could contain 1000 values. maybe more, maybe less.

 

[gerkintrigg]

I'd probably do something like use a foreach() loop to get the value of each and then do a test on each of them...

so something like:

 

if ($value is in one of the existing variables){
increment the appropriate variable value by 1;
}
else{
create a new variable and set it's value to 1;
}

 

Pseudo code only.... I have no idea HOW to do this.

[onlyican]

Sorry, not yet

[clearstatcache]

 

foreach($seat as $value) {

    if ( count(array_keys($seat, $value)) > 1 && !in_array($value, $duplicate) )

        $duplicate[] = $value;

}

 

[GingerRobot]

I couldn't get yours to work clearstatcache(which ive just noticed was my fault, whoops!), so here's mine. Looks like more code, but in a topic a while back, Barand showed that it was faster than using in_array().

 

 

<?php
$array = array('J/1' => 'J1'
,'J/2' => 'J2' 
,'J/3' => 'J3' 
,'J/4' => 'J1' 
,'J/5' => 'J3' 
,'J/6' => 'J6' 
,'J/7' => 'J7');
sort($array);//re-index array with numeric keys
$n = count($array);
for($x=0;$x<$n;$x++){
   for($y=$x+1;$y<$n;$y++){
       if($array[$x] == $array[$y]){
           echo 'Duplicate value:'.$array[$x].'<br />';
       }        
   }
}
?>

[jitesh]

<?php

$array_o = array("a","b","c","d","a","a","b");

$dup_arr = array();
$uni_arr = array();
foreach($array_o as $key => $value){
       if(!in_array($value,$uni_arr)){
   		$uni_arr[] = $value;
   }else{
   		$dup_arr[] = $value;
   }
}
$dup_arr = array_unique($dup_arr);
echo "<pre>";
print_r($dup_arr);
?>

[clearstatcache]

here's d complete code GingerRobot

 

<?php

 

$array = array('J/1' => 'J1'

,'J/2' => 'J2'

,'J/3' => 'J3'

,'J/4' => 'J1'

,'J/5' => 'J3'

,'J/6' => 'J6'

,'J/7' => 'J7');

 

$duplicate = array();

foreach($array as $value) {

    if ( count(array_keys($array, $value)) > 1 && !in_array($value, $duplicate) )

        $duplicate[] = $value;

}

print_r($duplicate);

 

[clearstatcache]

use check w/c gives the best performance...and of course u prefer more...

[GingerRobot]

Well, if you're interested:

 

<?php
$array = array('J/1' => 'J1'
,'J/2' => 'J2' 
,'J/3' => 'J3' 
,'J/4' => 'J1' 
,'J/5' => 'J3' 
,'J/6' => 'J6' 
,'J/7' => 'J7');
$duplicate = array();
$t1 = microtime(true);//start timer
for($i=0;$i<=10000;$i++){
    $duplicate = array();
    sort($array);//re-index array with numeric keys
    $n = count($array);
    for($x=0;$x<$n;$x++){
        for($y=$x+1;$y<$n;$y++){
            if($array[$x] == $array[$y]){
                $duplicate[] = $array[$x];
            }        
        }
    }
}
$t2 = microtime(true);//intermediate time
for($i=0;$i<=10000;$i++){
    $duplicate = array();
    foreach($array as $value) {
        if ( count(array_keys($array, $value)) > 1 && !in_array($value, $duplicate) )
            $duplicate[] = $value;
    }
}
$t3 = microtime(true);//end time

printf ("1st Method: %0.8f<br>2nd Method: %0.8f<br>Ratio (1st method/2nd method): %0.2f", $t2-$t1, $t3-$t2, ($t2-$t1)/($t3-$t2));

 

Results:

 

1st Method: 0.38158202
2nd Method: 0.52205086
Ratio (1st method/2nd method): 0.73

 

Of course, even over 10000 runs of each, there's still only aroun 0.1 of a second differance, so its not exactly all that important. Id probably use yours, for the less typing

 

Lastly, if the array already had numerical indexes and there was no need to sort, then the differance in speed between mine and yours is more noticeable

[onlyican]

OK

 

I did think there was a function in PHP which returned duplicated fields but I can't find one, so with my knowledge and your help, I built one

 

<?php
function GetDuplicatedValues($Array){

$DuplicatedValues 	= array();
//First check if function is needed
$UniqueArray = array_unique($Array);
if($Array != $ArrayUnique){
	//Loop through the Array
	foreach($Array as $Value){
		//Check if more than 1 Key is found for the value, Means Duplicate found
		if(count(array_key($Array, $Value)) > 1){
			//Add to new array
			$DuplicatedValues[] = $Value;
		}
	}
}
//Clear out duplicates
$DuplicatedValues = array_unique($DuplicatedValues);
return $DuplicatedValues;

}


$array = array('J/1' => 'J1'
,'J/2' => 'J2' 
,'J/3' => 'J3' 
,'J/4' => 'J1' 
,'J/5' => 'J3' 
,'J/6' => 'J6' 
,'J/7' => 'J7');

$DuplicateEntries = GetDuplicatedValues($array);


print_r($DuplicateEntires);

?>

 

$DuplicateEntires should return

 

[0] = J1

[1] = J3

[GingerRobot]

OK

 

I did think there was a function in PHP which returned duplicated fields but I can't find one, so with my knowledge and your help, I built one

 

Naa, there is a function that takes an array and removes all duplicates from it: array_unique(), but not one that just gives you the duplicates.