在C#中的F#List.map等效?
在C#中有没有相当于F#的List.map函数? 即对列表中的每个元素应用一个函数,并返回一个包含结果的新列表。
就像是:
public static IEnumerable<TResult> Map<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TResult> funky) { foreach (TSource element in source) yield return funky.Invoke(element); }
有没有内置的方式,或者我应该只写自定义扩展?
这是LINQ的Select
– 即
var newSequence = originalSequence.Select(x => {translation});
要么
var newSequence = from x in originalSequence select {translation};
ConvertAll
是内置函数:
public List<TOutput> ConvertAll<TOutput>( Converter<T, TOutput> converter )
自.NET 2.0以来可用。
MSDN代码示例:
using System; using System.Drawing; using System.Collections.Generic; public class Example { public static void Main() { List<PointF> lpf = new List<PointF>(); lpf.Add(new PointF(27.8F, 32.62F)); lpf.Add(new PointF(99.3F, 147.273F)); lpf.Add(new PointF(7.5F, 1412.2F)); Console.WriteLine(); foreach( PointF p in lpf ) { Console.WriteLine(p); } List<Point> lp = lpf.ConvertAll( new Converter<PointF, Point>(PointFToPoint)); Console.WriteLine(); foreach( Point p in lp ) { Console.WriteLine(p); } } public static Point PointFToPoint(PointF pf) { return new Point(((int) pf.X), ((int) pf.Y)); } } /* This code example produces the following output: {X=27.8, Y=32.62} {X=99.3, Y=147.273} {X=7.5, Y=1412.2} {X=27,Y=32} {X=99,Y=147} {X=7,Y=1412} */