scanning an array for dups

mojo

Hi,

After a multisort function, I have an array:

[3][IDnum] = ID03
[5][IDnum] = ID18
[6][IDnum] = ID27
[2][IDnum] = ID39
[4][IDnum] = ID39
[0][IDnum] = ID452
[1][IDnum] = ID890
there's also a [dup] element, all = 'No'

I want to write a while loop to scan this array.subelement, IDnum and find the two ID39 duplicates like this. When dups are found set the [dup] element to 'Yes'

Some pseudocode......

$i=0
start at top of sorted array (row [3])
$a = IDnum
skip one row
while ( $i <= the last row)
     $b = IDnum
     if $a = $b {
          set the [dup] element of the current row = 'Yes'
          skip one row backward
          set this row's [dup] element = 'Yes' also
          skip forward one row again
     }
     $a = $b     (swap vars for the next $a)
     skip another row    (move to next row for next $b)
     increment i
endwhile     (loop and start again with another $b)

how do you "start at the top of the current array" if my number element is not in order anymore?
how do you "skip" to the next row in the array?

thanks! :rolleyes:

mojo

ereptur

it's kind of hard to tell from your description. Is this a multidimensional array?

barand

Use the array indexes

	$array = array (
	0 => array (
			'ID' => 'ID452',
			'Dup' => 0
		),
	1 => array (
			'ID' => 'ID890',
			'Dup' => 0
		),
	2 => array (
			'ID' => 'ID39',
			'Dup' => 0
		),
	3 => array (
			'ID' => 'ID03',
			'Dup' => 0
		),
	4 => array (
			'ID' => 'ID39',
			'Dup' => 0
		),
	5 => array (
			'ID' => 'ID18',
			'Dup' => 0
		),
	6 => array (
			'ID' => 'ID27',
			'Dup' => 0
		)
	);
	//note - array not sorted

for ($i=0; $i<count($array)-2; $i++) {
	for ($j=$i+1; $j<count($array)-1; $j++) {
		if ($array[$i]['ID'] == $array[$j]['ID']) {
			$array[$i]['dup'] = 1;
			$array[$j]['dup'] = 1;
		}
	}
}

echo "<pre>";
print_r ($array);
echo "</pre>";

barand

If you ad this code, it'll sort the array on ID and preserve the indexes ( I noticed your other thread) using [man]uasort[/man] function

	// now sort it

function idsort($a,$b) {
      return strcmp($a['ID'],$b['ID']);
}

uasort ($array, 'idsort');

// check results of sort

echo "<pre>";
print_r ($array);
echo "</pre>";