Question

Hi I have a problem to manipulate an array with another array like the sample seen below.

Sample scenario

Array one contains elements A, B, C, D, E ordering is strict

B’s position is constant, it will not change in any manipulation

Array two contain X, Y

I need to merge array two with array one, merging result array will be:

Result array: X, B, Y, A, C D E

• A changed its position with X, because A’s position isnot constant
• B’s positions cannot changed, because B’s position is constant
• C changed its position with Y, because C’s position isnot constant
• A and C is appended after changes

Note:
More than one element’s positiob can be constant

What do you suggest for this kind of problem?

tHanks

Edit:

Thanks to @mkilmanas, I changed his code it works in the scenario described above

$arrayOne   =   array(
        0   =>  array('val' =>  'A','is_const'  =>  0),
        1   =>  array('val' =>  'B','is_const'  =>  1),
        2   =>  array('val' =>  'C','is_const'  =>  0),
        3   =>  array('val' =>  'D','is_const'  =>  0),
        4   =>  array('val' =>  'E','is_const'  =>  0)
);

$arrayTwo   =   array(
        0   =>  array('val' =>  'X','is_const'  =>  0),
        1   =>  array('val' =>  'Y','is_const'  =>  0)
);

//Clone arrayOne
$loose = $arrayOne;

//Collect Fixed Elements
$fixed = array();
foreach ($arrayOne as $idx=>$val){
    if ($val['is_const'] == 1){
        $fixed[] = $idx;
    }
}


//Now remove fixed elements
//PHP doesn't reindex the array, so it is safe to use foreach here
foreach($fixed as $idx) { unset($loose[$idx]); } 


//since they are numeric-indexed, they will be concatenated
//and the order is inverted, so that $arrayOne is appended to the end of $arrayTwo
$combined = array_merge($arrayTwo, $loose); 

// And now we insert the fixed elements at their fixed positions
foreach($fixed as $idx) {
   array_splice($combined, $idx, 0, array($arrayOne[$idx]));        
}

Result of $combined is X B Y A C D E which is correct

tHank you very much

Answer 1

I would use a combination of array_merge() and array_splice(). Lets assume that $fixed contains an array of fixed element’s keys (from $arrayOne).

$loose = $arrayOne; // Copy initial array

// Now remove fixed elements
// PHP doesn't reindex the array, so it is safe to use foreach here
foreach($fixed as $idx) { unset($loose[$idx]); } 

// since they are numeric-indexed, they will be concatenated
// and the order is inverted, so that $arrayOne is appended to the end of $arrayTwo
$combined = array_merge($arrayTwo, $arrayOne); 

// And now we insert the fixed elements at their fixed positions
foreach($fixed as $idx) {
    array_splice($combined, $idx, 0, array($arrayOne[$idx]));        
}
// voila - $combined should now have the desired order