PHP: How to identify AND CHANGE duplicate values in an array?

Question

OK, there are a lot of examples of duplicate detection and removal in php arrays, using array_unique() etc but what if you want to find dups, modify them, check again in a loop until all dups are now unique?

I think it's something like using array_filter()... so as a more specific example, here's what would come out of a sql statement something like this:

SELECT id, list.comboname 
FROM list
   INNER JOIN (
      SELECT comboname 
      FROM list
       GROUP BY comboname 
       HAVING count(id) > 1
   ) dup ON list.comboname = dup.comboname

To an array of the duplicates in the table:

Array ( 
    [0] => 49 
    [1] => big.dup  
    [2] => 233  
    [3] => another.duplicate  
    [4] => 653  
    [5] => big.dup  
    [6] => 387  
    [7] => big.dup  
    [8] => 729  
    [9] => another.duplicate  
    [10] => 1022  
    [11] => big.dup   
)

Now what I want is some PHP to delete characters until the period so they are unique [or add numbers if needed to the end]

So result would be:

Array (  
    [0] => 49  
    [1] => big.dup  
    [2] => 233  
    [3] => another.duplicate  
    [4] => 653  
    [5] => big.du  
    [6] => 387  
    [7] => big.d  
    [8] => 729  
    [9] => another.duplicat  
    [10] => 1022  
    [11] => big.dup1  
)

While retaining the original value (i.e. big.dup and another.duplicate)... I've looked through just about every PHP array function trying to imagine a strategy ... ideas?

why don't you finish this in MySQL? I think this would help you: stackoverflow.com/questions/7416545/… — kuzey beytar
– kuzey beytar, Commented Nov 20, 2011 at 22:05
A. Because I want to set it up to do the duplication removal automatically without changing and rerunning the SQL.. B. I don't want to just flag them, I want to change them to a non-duplicate and leave them — idea34
– idea34, Commented Nov 22, 2011 at 0:15

hakre · Accepted Answer · 2011-11-21 20:26:03Z

1

For the array in your question and for adding numbers at the end if a duplicate, you only need to loop over the array once and temporary build up a helper array that stores if a value has been already found (and how often):

$found = array();

foreach($array as &$value)
{
    if (is_int($value)) continue; # skip integer values

    if (isset($found[$value]))
    {
        $value = sprintf('%s-%d', $value, ++$found[$value]);
    }
    else
    {
        $found[$value] = 0;
    }
}
unset($value);

Demo

answered Nov 21, 2011 at 20:26

hakre

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Comments

ariefbayu · Accepted Answer · 2011-11-21 02:19:14Z

First of all, I think you have a rather complicated array structure.

Why don't you change it into something like:

$arr = array(
    '49' => 'big.dup',
    '233' => 'another.duplicate',
    '653' => 'big.dup',
    '387' => 'big.dup',
    '729' => 'another.duplicate',
    '1022' => 'big.dup',
);

This way, you can easily check for duplicate using something like this:

$arr = array(
    '49' => 'big.dup',
    '233' => 'another.duplicate',
    '653' => 'big.dup',
    '387' => 'big.dup',
    '729' => 'another.duplicate',
    '1022' => 'big.dup',
);
$arr_val = array();
foreach( $arr as $key => $val)
{
    if(isset($arr_val[ $val ]))
    {
        $arr_val[ $val ]++;
        $arr[ $key ] = $val . $arr_val[ $val ];
    }
    else
    {
        $arr_val[ $val ] = 0;
    }
}

Or, if you insist on using that complicated array structure, you can modify code above into this:

$arr_val = array();
foreach( $arr as $key => $val)
{
    if(isset($arr_val[ $val ]) && !is_numeric( $val ) )
    {
        $arr_val[ $val ]++;
        $arr[ $key ] = $val . $arr_val[ $val ];
    }
    else
    {
        $arr_val[ $val ] = 0;
    }
}

You may notice that there's not much different here. I just add && !is_numeric($val) to it as I think, you wouldn't want to process the ID. Though, I still think that the ID will never duplicate.

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