Question

如何将以下foreach循环转换为linq等效？ foreach循环还是linq表现更好？这里的项目数量有限，可能在100s。提前谢谢。

 System.out.println("~~~~~WELCOME~~~~~");

      do{
          do{
            System.out.println("\nPlease enter item code");
              System.out.print("#");
            itemCode = br.readLine();
            itemCodeCorrect = isItemCodeCorrect(itemCode);

            }while(!itemCodeCorrect);

          do{


            System.out.println("\nPlease enter item description");
            itemDesc = br.readLine();

            itemDescCorrect = isItemDescCorrect(itemDesc);



             }while(!itemDescCorrect);


          do{

          try{
            System.out.println("\nPlease enter item weight");
            itemWeight = Double.parseDouble(br.readLine());


          }catch(NumberFormatException ex){


              System.out.println("\n" +ex +"\nInvalid input. Item must be in a number format. Please try again");
              }  

          }while(itemWeight == 0);






          do{
              try{
            System.out.println("\nPlease enter the item price");

            itemUnitPrice = Double.parseDouble(br.readLine());
                 }catch(NumberFormatException ex){

                  System.out.println("\n" +ex +"\nInvalid input. Item must be in a number format. Please try again.");
                                                  }

            }while(itemUnitPrice == 0);

Allitems = new Items(itemCode, itemDesc, itemWeight, itemUnitPrice, quantity, Total, TotalCost, TotalWeight);
v.add(Allitems);

Answer 1

您可以使用此查询使用匿名类型来存储中间结果：

List<ListItem> items = ListValueString.Split(new char[] { ';' }, StringSplitOptions.RemoveEmptyEntries)
    .Select(lstItem => new { lstItem, listTexts = lstItem.Split(':') })
    .Select(x => new ListItem()
    {
        ListText = x.listTexts[0],
        ListId = Int32.Parse(x.listTexts[1]),
        IsActive = true,
        IsInUse = Int32.Parse(x.listTexts[1]) == _defaultString
    })
    .ToList();
var _ListItems = new ObservableCollection<ListItem>(items);

LINQ也使用循环，因此没有明显的性能差异。

将foreach循环转换为Linq表达式

1 个答案: