考虑三个不同的字符串列表,其中一个是列表列表。我需要全部搜索才能找到一个特定的。
在这个示例中,结果已经实现,但我想用一个Linq语句来实现它。请注意,我不想更改现有集合,也不想创建任何新集合。
var collectionA = new List<string>() {"Item1", "Item2"};
var collectionB = new List<string>() { "Item3", "Item4" };
var listOfLists = new List<List<string>>() {new List<string>() {"Item5", "Item6"}, new List<string>(){ "Item7", "Item8"}};
//Is there a better Linq way to do this?
var searchString = "Item5";
var item = collectionA.FirstOrDefault(i => i == searchString);
if (item == null)
{
item = collectionB.FirstOrDefault(i => i == searchString);
if (item == null)
{
foreach (var listOfList in listOfLists)
{
item = listOfList.FirstOrDefault(i => i == searchString);
if (item != null)
{
break;
}
}
}
}
bool result = listOfLists.SelectMany(x => x)
.Concat(collectionA)
.Concat(collectionB)
.Any(x => x == "Item5");
var result = collectionA
.Concat(collectionB)
.Concat(listOfLists.SelectMany(i => i))
.FirstOrDefault(i => i == searchString);
您可以使用SelectMany
来压平列表的列表,首先将collectionA
和collectionA
添加到listOfLists
中:
listOfLists.AddRange(new[] {collectionA, collectionB});
if (listOfLists.SelectMany(x => x).Any(y => y == "Item5"))
{
}
有了你的新编辑,它不喜欢改变现有的收藏,也不喜欢创建新的收藏,你可以做:
if (listOfLists.Any(x => x.Any(y => y == "Item5"))
|| collectionA.Any(x => x == "Item5")
|| collectionB.Any(x => x == "Item5"))
{
}
也许这会有所帮助:
var collectionA = new List<string>() { "Item1", "Item2" };
var collectionB = new List<string>() { "Item3", "Item4" };
var listOfLists = new List<List<string>>() { new List<string>() { "Item5", "Item6" }, new List<string>() { "Item7", "Item8" } };
var val = from y in (from x in listOfLists[0] select x) where y == "Item5" select y;
您可以修改更多以获得预期结果