使用 LINQ 将多个列表合并为一个列表 [英] Merge multiple Lists into one List with LINQ
问题描述
是否有一种巧妙的方法可以使用 LINQ 将多个 List 合并为一个 List 以有效地复制它?
Is there a slick way to merge multiple Lists into a single List using LINQ to effectively replicate this?
public class RGB
{
public int Red { get; set; }
public int Green { get; set; }
public int Blue { get; set; }
public RGB(int red, int green, int blue) { Red = red; Green = green; Blue = blue; }
}
public void myFunction()
{
List<int> red = new List<int> { 0x00, 0x03, 0x06, 0x08, 0x09 };
List<int> green = new List<int> { 0x00, 0x05, 0x06, 0x07, 0x0a };
List<int> blue = new List<int> { 0x00, 0x02, 0x03, 0x05, 0x09 };
List<RGB> colors = new List<RGB>();
colors.Add(new RGB(red[0], green[0], blue[0]));
colors.Add(new RGB(red[1], green[1], blue[1]));
colors.Add(new RGB(red[2], green[2], blue[2]));
colors.Add(new RGB(red[3], green[3], blue[3]));
colors.Add(new RGB(red[4], green[4], blue[4]));
}
或者,由于列表是分开到达的,像下面这样按顺序合并它们会更有效.
Or, since the lists arrive separately, its more effective to merge them sequentially like the following.
public class RGB
{
public int Red { get; set; }
public int Green { get; set; }
public int Blue { get; set; }
public RGB(int red, int green, int blue) { Red = red; Green = green; Blue = blue; }
}
public void myFunction()
{
List<int> red = new List<int> { 0x00, 0x03, 0x06, 0x08, 0x09 };
List<RGB> colors = new List<RGB>();
colors.Add(new RGB(red[0], 0, 0));
colors.Add(new RGB(red[1], 0, 0));
colors.Add(new RGB(red[2], 0, 0));
colors.Add(new RGB(red[3], 0, 0));
colors.Add(new RGB(red[4], 0, 0));
List<int> green = new List<int> { 0x00, 0x05, 0x06, 0x07, 0x0a };
colors[0].Green = green[0];
colors[1].Green = green[1];
colors[2].Green = green[2];
colors[3].Green = green[3];
colors[4].Green = green[4];
List<int> blue = new List<int> { 0x00, 0x02, 0x03, 0x05, 0x09 };
colors[0].Blue = blue[0];
colors[1].Blue = blue[1];
colors[2].Blue = blue[2];
colors[3].Blue = blue[3];
colors[4].Blue = blue[4];
}
推荐答案
您实际上是在尝试压缩三个集合.如果只有 LINQ Zip()
方法支持同时压缩两个以上.但可惜,它一次只支持两个.但我们可以让它发挥作用:
You're essentially trying to zip up three collections. If only the LINQ Zip()
method supported zipping up more than two simultaneously. But alas, it only supports only two at a time. But we can make it work:
var reds = new List<int> { 0x00, 0x03, 0x06, 0x08, 0x09 };
var greens = new List<int> { 0x00, 0x05, 0x06, 0x07, 0x0a };
var blues = new List<int> { 0x00, 0x02, 0x03, 0x05, 0x09 };
var colors =
reds.Zip(greens.Zip(blues, Tuple.Create),
(red, tuple) => new RGB(red, tuple.Item1, tuple.Item2)
)
.ToList();
当然,编写一个扩展方法来做三个(或更多)并不是很痛苦.
Of course it's not terribly painful to write up an extension method to do three (or more).
public static IEnumerable<TResult> Zip<TFirst, TSecond, TThird, TResult>(
this IEnumerable<TFirst> first,
IEnumerable<TSecond> second,
IEnumerable<TThird> third,
Func<TFirst, TSecond, TThird, TResult> resultSelector)
{
using (var enum1 = first.GetEnumerator())
using (var enum2 = second.GetEnumerator())
using (var enum3 = third.GetEnumerator())
{
while (enum1.MoveNext() && enum2.MoveNext() && enum3.MoveNext())
{
yield return resultSelector(
enum1.Current,
enum2.Current,
enum3.Current);
}
}
}
这让事情变得更好:
var colors =
reds.Zip(greens, blues,
(red, green, blue) => new RGB(red, green, blue)
)
.ToList();
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