php array：如何在關聯數組中訪問“ $ key-1”？

Question

我有一組條件的現有foreach，我想保持原樣，並添加結束日期，該日期是該行的開始日期+一天之前

我如何訪問“ $ line-1”來執行以下操作：

foreach($tab as $line){
       if the line before with $line[beginning_date] exists
           $line[end_date]=   the line before with $line[beginning_date] value +1
 }

Answer 1

夠好了？

$theLineBefore = null;
foreach($tab as $line){
       if the line before with $line[beginning_date] exists
           $line[end_date]=   the line before with $line[beginning_date] value +1
  $theLineBefore = $line;
 }