如何将此 linq 转换为 bool

Question

如何将查询转换为布尔值？我使用了“ALL (x => x)”，但没有给出我需要的答案。

代码行

checkItemInventory.Where(x => listCost.Contains(x.Id));

在这种情况下，listcost将有2项目，我需要检查是否checkItemInventory有这些2项目。

Answer 1

“库存中的所有物品都有一个出现在 listcost 中的 id”。listCost 需要与库存相同数量的项目（假设 Id 是唯一的）可能更多，才有机会返回 truecheckItemInventory.All(x => listCost.Contains(x.Id))“库存中至少有一件物品的 id 也在 listCost 中”。Listcost 至少可以只有一个 id，才有机会返回 truecheckItemInventory.Any(x => listCost.Contains(x.Id))如您所见，这些都不是您想要的，因为您似乎在说您想检查 listcost 中的每个项目是否也存在于库存中。这就像顶部代码，但反过来（“listCost 中的所有项目都存在于库存中”与“库存中的所有项目都存在于 listcost 中”我想我会先从库存中制作一本字典，除非它已经支持快速查找：var d = checkItemInventory.Select(x => new { x.Id, x.Id }).ToDictionary();var boolResult = listCost.All(lc => d.ContainsKey(lc));如果库存很小，您可以使用这种方法：listCost.All(lc => checkItemInventory.Any(cii => cii.Id == lc));请注意，在内部它可能会执行以下操作：bool all = true;foreach(lc in listCost){&nbsp; bool found = false;&nbsp; foreach(cci in checkItemInventory)&nbsp; &nbsp; if(lc == cci.Id){&nbsp; &nbsp; &nbsp; found = true;&nbsp; &nbsp; &nbsp; break;&nbsp; &nbsp; }&nbsp; all &= found;&nbsp; if(!all)&nbsp; &nbsp; return false;}return true;这是很多重复比较（对于 listCost 中的每个项目，都会扫描整个库存），可能会很慢编辑我要求澄清您如何存储库存和建造物品的成本。这是我做出的一个假设，以及基于它的解决方案如何工作：假设您的库存中有物品的种类和计数，说明玩家携带了多少物品：class InventoryItem{&nbsp; int ItemKindId { get; set;}&nbsp; int CountOf { get; set; }}player.Inventory.Add(new InventoryItem() {&nbsp;&nbsp; ItemKindId = Constants.WOOD, //1&nbsp; CountOf = 10 //holding 10 items of wood};player.Inventory.Add(new InventoryItem() {&nbsp;&nbsp; ItemKindId = Constants.STONE, //2&nbsp; CountOf = 5 //holding 5 items of stone};假设你有一个制作斧头的配方，它需要 1 个木头和 2 个石头，但它以简单的顺序列出它们：int[] axeRecipe = new int[] { Constants.WOOD, Constants.STONE, Constants.STONE };可能最容易对配方进行分组：var recipe = axeRecipe.GroupBy(item => item)/*&nbsp; now we have a grouping of the recipe[item].Key as the material and a&nbsp; recipe[item].Count() of how much. The group is like a dictionary:&nbsp; recipe[Constants.WOOD] = new List<int>{ Constants.WOOD };&nbsp; recipe[Constants.STONE] = new List<int>{ Constants.STONE, Constants.STONE, };&nbsp; A group item has a Key and a list of objects that have that key&nbsp; Because my recipe was simply ints, the Key is the same number as all the&nbsp;&nbsp; items in the list*///for all items in the recipegrp.All(groupItem =>&nbsp; //does the player inventory contain any item&nbsp; playerInventory.Any(inventoryItem =>&nbsp;&nbsp; &nbsp; //where the material kind is the same as the recipe key (material)&nbsp; &nbsp; inventoryItem.ItemKindId == groupItem.Key &&&nbsp; &nbsp; //and the count they have of it, is enough to make the recipe&nbsp; &nbsp; inventoryItem.CountOf >= groupItem.Count());如果需要，您当然可以将其减少为一行：axeRecipe.GroupBy(...).All(...)

Answer 2

您告诉我们以下内容：如何将查询转换为布尔值？我使用了“ALL (x => x)”，但没有给出我需要的答案。checkItemInventory.Where(x => listCost.Contains(x.Id));在这种情况下，listcost 将有 2 个项目，我需要检查 checkItemInventory 是否有这 2 个项目。如果您需要检查是否有任何结果，那么您可以使用：bool&nbsp;hasItems&nbsp;=&nbsp;checkItemInventory.Where(x&nbsp;=>&nbsp;listCost.Contains(x.Id)).Any();如果您需要计算结果，您可以使用&nbsp;checkItemInventory.Where(x&nbsp;=>&nbsp;listCost.Contains(x.Id)).Count();

Answer 3

您可以使用 aJoin创建基于方法的 Linq 查询，并使用结果检查列表的长度是否大于 0。然后将其转换为布尔值。var query = checkItemInventory.Join(listCost,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; inventory => inventory.Id,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; cost => cost.Id,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; (inventory, cost) => new { id = inventory.Id });var count = query.ToList().Count();var b = (count > 0);

Answer 4

您可以将 映射listCost到列表，int然后使用Except()andAny()来检查是否包含所有项目：bool&nbsp;containsAll&nbsp;=&nbsp;!listCost.Select(x&nbsp;=>&nbsp;x.Id).Except(checkItemInventory).Any();