.NET Framework DefaultIfEmpty
示例
var numbers = new[] {2,4,6,8,1,3,5,7};
var numbersOrDefault = numbers.DefaultIfEmpty();
Console.WriteLine(numbers.SequenceEqual(numbersOrDefault)); //True
var noNumbers = new int[0];
var noNumbersOrDefault = noNumbers.DefaultIfEmpty();
Console.WriteLine(noNumbersOrDefault.Count()); //1
Console.WriteLine(noNumbersOrDefault.Single()); //0
var noNumbersOrExplicitDefault = noNumbers.DefaultIfEmpty(34);
Console.WriteLine(noNumbersOrExplicitDefault.Count()); //1
Console.WriteLine(noNumbersOrExplicitDefault.Single()); //34
热门推荐
10 儿子立冬祝福语简短独特
11 对当兵的祝福语简短
12 侄儿高考试祝福语简短
13 伴郎红包祝福语朋友简短
14 媳妇生日简短祝福语朋友
15 公司年会祝福语简短最好
16 元旦感恩祝福语简短大全
17 红包祝福语简短10字
18 周六早晨祝福语简短