13,000
回編集
「LINQ - 要素の取得」の版間の差分
ナビゲーションに移動
検索に移動
→要素の取得(単一)
| 65行目: | 65行目: | ||
Console.WriteLine(source.ElementAt(2)); | Console.WriteLine(source.ElementAt(2)); | ||
// | // -> 5 | ||
Console.WriteLine(source.ElementAtOrDefault(10)); | Console.WriteLine(source.ElementAtOrDefault(10)); | ||
// | // -> 0 | ||
Console.WriteLine(source.First()); | Console.WriteLine(source.First()); | ||
// | // -> 3 | ||
Console.WriteLine(source.First(e => e > 5)); | Console.WriteLine(source.First(e => e > 5)); | ||
// | // -> 6 | ||
var emptyList = new List<int>(); | |||
Console.WriteLine($"FirstOrDefault() on empty list: {emptyList.FirstOrDefault()}"); | |||
// -> int型のデフォルト値 : 0 | |||
Console.WriteLine(source.Last()); | Console.WriteLine(source.Last()); | ||
// | // -> 9 | ||
Console.WriteLine(source.Last(e => e < 5)); | Console.WriteLine(source.Last(e => e < 5)); | ||
// | // -> 4 | ||
Console.WriteLine(source.LastOrDefault(x => x > 10)); | |||
// -> int型のデフォルト値 : 0 | |||
Console.WriteLine(source.Single()); | Console.WriteLine(source.Single()); | ||
// | // -> System.InvalidOperationException: シーケンスに複数の要素が含まれている | ||
Console.WriteLine(source.Single(e => e < 4 )); | Console.WriteLine(source.Single(e => e < 4 )); | ||
// | // -> 3 | ||
Console.WriteLine(source.SingleOrDefault(x => x == 3)); | |||
// -> 3 | |||
</syntaxhighlight> | </syntaxhighlight> | ||
<br><br> | <br><br> | ||