.NET Framework 第一或默认
例子
var numbers = new[] {1,2,3,4,5};
var firstNumber = numbers.FirstOrDefault();
Console.WriteLine(firstNumber); //1
var firstEvenNumber = numbers.FirstOrDefault(n => (n & 1) == 0);
Console.WriteLine(firstEvenNumber); //2
var firstNegativeNumber = numbers.FirstOrDefault(n => n < 0);
Console.WriteLine(firstNegativeNumber); //0
var words = new[] { "one", "two", "three", "four", "five" };
var firstWord = words.FirstOrDefault();
Console.WriteLine(firstWord); //一
var firstLongWord = words.FirstOrDefault(w =>w.Length> 3);
Console.WriteLine(firstLongWord); //三
var firstMissingWord = words.FirstOrDefault(w =>w.Length> 5);
Console.WriteLine(firstMissingWord); //空值
热门推荐
10 生日宴祝福语 简短独特
11 520送给女友祝福语简短
12 生完孩子祝福语简短
13 小学同学简短祝福语
14 紫玫瑰生日祝福语简短
15 退休的祝福语简短精辟
16 小朋友得奖祝福语简短
17 长辈请客祝福语简短精辟
18 爸爸寿宴仪式祝福语简短