RX中的Linq操作符

Combining different sequences

    1. Concat

var source1 = Observable.Range(1, 3);
var source2 = Observable.Range(1, 3);
source1.Concat(source2)
       .Subscribe(Console.WriteLine);
Console.ReadLine();

    结果输出：123123
    2. Merge

var source1 = Observable.Range(1, 3);
var source2 = Observable.Range(1, 6);
source1.Merge(source2)
       .Subscribe(Console.WriteLine);
Console.ReadLine();

    结果输出：112233456
    3. Merge、CombineLatest、and Zip -the "and" and "or" in RX

IObservable<float> o1;
IObservable<int> o2;
IObservable<string> o3;
var result=Observable.Merge(o1.Select(_ =>true),o2.Select(_ =>true),o3.Select(_ =>true));

           Merge是“Or”，Merge是无状态的，一旦第一个O1满足条件，无法判定O2和O3

Subject<int> s1;
Subject<int> s2;
s1.CombineLatest(s2,(a,b)=>a*b).Subscribe(Console.WriteLine);

          s1.OnNext(5); //Nothing happens,no values for s2
          s2.OnNext(10);//10 came in,combine the 10 with whatever s1 was (5)

          >>>>>50

          s2.OnNext(20);//20 came in,still use the s1's latest value

          >>>>>100

          s1.OnNext(2);// s1 is 1,take s2's latest value(20);

          >>>>>40

Subject<int> s1;
Subject<int> s2;
s1.Zip(s2,(a,b)=>a*b).Subscribe(Console.WriteLine);

          s1.OnNext(2);//Nothing ,no pair yet

          s1.OnNext(5);//still no pair

          s2.OnNext(10);(2,10),send it down

          s1.OnNext(10);//s2's empty,no pair

          s2.OnNext(1);// 5*1

          s2.OnNext(10);//10*10

          s2.OnNext(100);//s1's empty,no output

    4. Catch

var source1 = Observable.Range(1, 3);
var source2 = Observable.Range(4, 3);
source1.Catch(source2)
       .Subscribe(Console.WriteLine);
Console.ReadLine();

    结果输出：123，只要source1正确，就不输出source2。确定问题在哪
    5. OnErrorResumeNext

var source1 = Observable.Throw<int>(new Exception("An error has occurred."));
var source2 = Observable.Range(4, 3);
source1.OnErrorResumeNext(source2)
       .Subscribe(Console.WriteLine);
Console.ReadLine();

    不确定问题定位，确定有异常，一定要输出。456

Projection

     The Select operator can translate each element of an observable sequence into another form.

var seqNum = Observable.Range(1, 5);
var seqString = from n in seqNum
                select new string('*', (int)n);
seqString.Subscribe(str => { Console.WriteLine(str); });
Console.ReadKey();

     an extension of the .NET event conversion

var frm = new Form();
IObservable<EventPattern<MouseEventArgs>> move = Observable.FromEventPattern<MouseEventArgs>(frm, "MouseMove");
IObservable<System.Drawing.Point> points = from evt in move
                                          select evt.EventArgs.Location;
points.Subscribe(pos => Console.WriteLine("mouse at " + pos));
Application.Run(frm);

Filtering

    “Where” Operation

IObservable<int> seq = Observable.Generate(0, i => i < 10, i => i + 1, i => i * i);
IObservable<int> source = from n in seq
                          where n < 15
                          select n;
source.Subscribe(x => {Console.WriteLine(x);});   // output is 0, 1, 4, 9
Console.ReadKey();

    Event Where Operation

var frm = new Form(); 
IObservable<EventPattern<MouseEventArgs>> move = Observable.FromEventPattern<MouseEventArgs>(frm, "MouseMove");
IObservable<System.Drawing.Point> points = from evt in move
                                          select evt.EventArgs.Location;
var overfirstbisector = from pos in points
                        where pos.X == pos.Y 
                        select pos;
var movesub = overfirstbisector.Subscribe(pos => Console.WriteLine("mouse at " + pos));
Application.Run(frm);

Time-based Operation

var seq = Observable.Interval(TimeSpan.FromSeconds(1));
var bufSeq = seq.Buffer(5);
//var bufSeq = seq.Buffer(TimeSpan.FromSeconds(5));
bufSeq.Subscribe(values => Console.WriteLine(values.Sum()));
Console.ReadKey();