UniRx第二季学习[linq与UniRx](三) ------ SelectMany/Take/Concat/WhenAll

课程地址 : http://www.sikiedu.com/my/course/293

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一.SelectMany

功能 ：将序列的每个元素投影到 IEnumerable<T> 并将结果序列合并为⼀个序列。对每项再进⾏遍历处理再进⾏合成序列。（这可能不太理解，看完示例就明白了）

1.linq

 public class LINQSelectManyExample : MonoBehaviour
    {
        class Student
        {
            public string Name;
            public int Age;
        }
        private void Start()
        {
            var students = new List<Student>()
            {
                new Student() {Name = "张三", Age = 50},
                new Student() {Name = "张三", Age = 45},
                new Student() {Name = "李四", Age = 50}
            };
            var singleChars = students.SelectMany(student => student.Name + ":" +
      student.Age);

            foreach (var singleChar in singleChars)
            {
                Debug.Log(singleChar);
            }
        }
    }
}

运行效果 :

 2.UniRx

 public class SelectManyExample : MonoBehaviour
    {
        void Start()
        {
            var urls = new List<string> { "http://sikiedu.com", "http://qframework.com" };
            urls.SelectMany(url => "[" + url + "]")
                .ToList()
                .ForEach(singleChar =>
                {
                    Debug.Log(singleChar);
                });
        }
    }

运行效果：

 ⼀般在 UniRx 中，主要是完成 Coroutine 的顺序执⾏功能。

 public class CoroutineSequenceExample : MonoBehaviour
    {
        IEnumerator A()
        {
            yield return new WaitForSeconds(1.0f);
            Debug.Log("A");
        }

        IEnumerator B()
        {
            yield return new WaitForSeconds(1.0f);
            Debug.Log("B");
        }

        IEnumerator C()
        {
            yield return new WaitForSeconds(1.0f);
            Debug.Log("C");
        }

        // Use this for initialization
        void Start()
        {
            var aStream = Observable.FromCoroutine(A);
            var bStream = Observable.FromCoroutine(B);
            var cStream = Observable.FromCoroutine(C);

            aStream.SelectMany(bStream.SelectMany(cStream))
                   .Subscribe();
        }
    }

二.Take

功能 : 从序列的开头返回指定数量的相邻元素。

1.linq

public class LINQTakeExample : MonoBehaviour
    {
        void Start()
        {
            var urls = new string[] {
                "http://sikiedu.com",
                "http://qframeowork.io",
                "http://weibo.com",
                "http://github.com",
            };

            urls.Take(3)
                .ToList()
                .ForEach(url =>
                {
                    Debug.Log(url);
                });
        }
    }

2.UniRx

public class UniRxTakeExample : MonoBehaviour
    {
        void Start()
        {
            Observable.EveryUpdate()
                      .Where(_ => Input.GetMouseButtonDown(0))
                      .Take(2)
                      .Subscribe(_ => { Debug.Log("mouse clicked!"); });
        }
    }

值由前两次鼠标点击才会输出

三.Concat

功能 : 连接两个序列。

1.Linq

public class LINQConcatExample : MonoBehaviour
    {
        void Start()
        {
            var aClassAges = new[] { 3, 4, 5, 6 };
            var bClassAges = new[] { 1, 3, 5, 7 };

            aClassAges.Concat(bClassAges)
                      .ToList()
                      .ForEach(age =>
                      {
                          Debug.Log(age);
                      });
        }
    }

2.UniRx

public class UniRxConcatExample : MonoBehaviour
    {
        void Start()
        {
            var leftMouseClickStream = Observable.EveryUpdate().Where(_ => Input.GetMouseButtonDown(0)).Take(3).Select(_ => "A");
            var rightMouseClickStream = Observable.EveryUpdate().Where(_ => Input.GetMouseButtonDown(1)).Take(2).Select(_ => "B");

            leftMouseClickStream.Concat(rightMouseClickStream)
                                .Subscribe(clickEvent =>
                                {
                                    Debug.Log(clickEvent);
                                });
        }
    }

按三次左键再按两次右键，输出A A A B B(否则不输出)

四.WhenAll

功能 ：确定序列中的所有元素是否都满⾜条件(Linq)，按照条件执行完后执行注册事件（UniRx）。

1.linq(All操作符)

public class LINQWhenAllExample : MonoBehaviour
    {
        void Start()
        {
            var ages = new int[] { 18, 19, 20, 10, 50, 100 };

            Debug.Log(ages.All(age => age > 10));
        }
    }

2.UniRx

 public class UniRxWhenAllExample : MonoBehaviour
    {
        IEnumerator A()
        {
            yield return new WaitForSeconds(1.0f);
            Debug.Log("A");
        }

        IEnumerator B()
        {
            yield return new WaitForSeconds(1.0f);
            Debug.Log("B");
        }

        void Start()
        {
            var leftClickStream = Observable.EveryUpdate().Where(_ => Input.GetMouseButtonDown(0)).Take(3).Select(_ =>
            {
                Debug.Log("left mouse clicked");
                return Unit.Default;
            });

            var rightClickStream = Observable.EveryUpdate().Where(_ => Input.GetMouseButtonDown(1)).Take(4).Select(_ =>
            {
                Debug.Log("right mouse clicked");
                return Unit.Default;
            });

            Observable.WhenAll(Observable.FromCoroutine(A),
                               Observable.FromCoroutine(B),
                               leftClickStream,
                               rightClickStream)
                      .Subscribe(_ =>
                      {
                          Debug.Log("all coroutine completed");
                      });
        }
    }

运行结果 :

这里顺序不一定如此