比较两个列表：一个包含对象，另一个包含字符串

Question

I'm trying to compare two list to add (in an other list) my lights that I want. I want to get light object by string name

For the moment, I'm using a double foreach, but I know it's possible with LinQ but I don't know how...

private readonly string[] lightsWanted = { "MyLight1", "MyLight2" };
---
var lights = await this.bridgeManager.GetLights();
foreach (Light light in lights)
{
    foreach (string lightWanted in this.lightsWanted)
    {
        if (light.Name == lightWanted)
        {
            this.selectedLights.Add(light);
        }
    }
}

Thank you for your help.

Answer 1

Using a Where and Contains (not as efficient).

List<Light> lightsIWant = (await this.bridgeManager.GetLights())
    .Where(l => lightsWanted.Contains(l.Name))
    .ToList();

Using a Join (more efficient)

var allLights = await this.bridgeManager.GetLights();
IEnumerable<Light> lightsIWant = from allLight in allLights
                                 join desiredLightName in lightsWanted 
                                     on allLight.Name equals desiredLightName
                                 select allLight;

You can do a Join using Extension Methods as well, I just prefer using the query syntax for simple stuff like this.

Answer 2

您可以为此目的使用 Join

var selectedList = lights.Join(lightsWanted,x=>x.Name,y=>y,(x,y)=>x);

Answer 3

This should do it:

List<Light> lightsIwant = (from l in lights
                           join lw in lightsWanted on l.Name equals lw
                           select l).ToList();