php - Minus two numbers in a foreach loop and display result for each result -

i have foreach loop below.

i'm looking minus $wrap->wrap_total 1 came before in loop , struggling!

foreach ($wrap_query->result() $wrap) {     echo date("d d m y", strtotime($wrap->wrap_date))." - ";     echo money_format('%n', $wrap->wrap_total)." - ";      echo "<br />"; } 

current output below:

sun 07 aug 2016 - £10,000.00

sat 06 aug 2016 - £12,000.00

fri 05 aug 2016 - £8,000.00

what i'd is:

sun 07 aug 2016 - £10,000.00 (-£2,000)

sat 06 aug 2016 - £12,000.00 (£4,000)

fri 05 aug 2016 - £8,000.00

any , appreciated!

the commented code below might started. demo can found here well.

    <?php          setlocale(lc_monetary, 'en_gb');           // let imagine moment $wrap_query->result() contains         // following simulated data mimicking data structure...         $simulatedwrap1     = new stdclass();         $simulatedwrap2     = new stdclass();         $simulatedwrap3     = new stdclass();          $simulatedwrap1->wrap_date  = "2016-08-07";         $simulatedwrap1->wrap_total = 10000.00;          $simulatedwrap2->wrap_date  = "2016-08-06";         $simulatedwrap2->wrap_total = 12000.00;          $simulatedwrap3->wrap_date  = "2016-08-05";         $simulatedwrap3->wrap_total = 8000.00;          $rwrapcollection    = [             $simulatedwrap1,             $simulatedwrap2,             $simulatedwrap3,         ];          // make copy of main array collection         // used within loop move array cursor         // next element within collection         $rwrapclone         = $rwrapcollection;          // fun: explicitly move cursor first         // element in collection         current($rwrapclone);          // create , initialize variable $output empty string.         // variable hold html content generated within loop         $output             = "";          foreach ($rwrapcollection $index=>$wrap){             // move cursor next item & catch value in variable              $nextwrap       = next($rwrapclone);             $output        .= date("d d m y", strtotime($wrap->wrap_date)) . " - ";             $output        .= money_format('%n', $wrap->wrap_total);              // if there still next item, calculate             // difference between current & next item                    if($nextwrap){                 $difference = $wrap->wrap_total - $nextwrap->wrap_total;                 $output    .= " (" . money_format('%n',$difference) . ")";             }              $output .= "<br />";         }          echo $output;          //produces:         sun 07 aug 2016 - £10,000.00 (-£2,000.00)         sat 06 aug 2016 - £12,000.00 (£4,000.00)         fri 05 aug 2016 - £8,000.00 

effective code relates unique case:

    <?php          $output         = "";         $resultscopy    = $wrap_query->result();         current($resultscopy);          foreach ($wrap_query->result()  $wrap) {             $nexwrap        = next($resultscopy);             $output        .= date("d d m y", strtotime($wrap->wrap_date)) . " - ";             $output        .= money_format('%n', $wrap->wrap_total);              if($nexwrap){                 $difference = $wrap->wrap_total - $nexwrap->wrap_total;                 $output    .= " (" . money_format('%n',$difference) . ")";             }              $output .= "<br />";         }          echo $output;