Implode sorted number array to string by commas and merge intervals

Question

I would like to implode an array, but with one difference. I would like to merge intervals with a - sign. How can this be done? (The array is ordered!)

Answer 1

    $oldArray=array(2,4,5,6,8,10);

    $newArray=array();


    foreach($oldArray as $count=>$val){
        if($count==0){
            //begin sequencing
            $sequenceStart=$sequenceEnd=$val;
        }

        if($val==$sequenceEnd+1){
            $sequenceEnd=$val;
            continue;
        }else{
            if($sequenceEnd==$val){
                //do nothing
                continue;
            }


        }

        //new sequence begins 
        //save new sequence
        if($sequenceStart==$sequenceEnd){
            //sequnce is a single number
            $newArray[]=$sequenceEnd;
        }else{
            $newArray[]=$sequenceStart.'-'.$sequenceEnd;
        }

        //reset sequence
        $sequenceStart=$sequenceEnd=$val;
    }

    //new sequence begins 
    //save new sequence
    if($sequenceStart==$sequenceEnd){
        //sequnce is a single number
        $newArray[]=$sequenceEnd;
    }else{
        $newArray[]=$sequenceStart.'-'.$sequenceEnd;
    }

    //reset sequence
    $sequenceStart=$sequenceEnd=$val;



    return implode(',', $newArray);