C# Set.First方法代码示例

 public void ShouldAdd()
 {
     var collection = new Set<string>();
     collection.Add("1");
     collection.Add("2");
     Assert.AreEqual(2, collection.Count);
     Assert.AreEqual("1", collection.First());
     Assert.AreEqual("2", collection.Last());
 }

 public void ShouldRemove()
 {
     var collection = new Set<string>();
     collection.Add("1");
     collection.Add("2");
     collection.Remove("1");
     collection.Remove(null);
     Assert.AreEqual(1, collection.Count);
     Assert.AreEqual("2", collection.First());
 }

 public void ShouldNotAddNulls()
 {
     var collection = new Set<string>();
     collection.Add(null);
     collection.Add("1");
     collection.Add(null);
     collection.Add(null);
     Assert.AreEqual(1, collection.Count);
     Assert.AreEqual("1", collection.First());
 }

        internal override BoolExpr<DomainConstraint<BoolLiteral, Constant>> FixRange(Set<Constant> range, MemberDomainMap memberDomainMap)
        {
            Debug.Assert(range.Count == 1, "For BoolLiterals, there should be precisely one value - true or false");
            var scalar = (ScalarConstant)range.First();
            var expr = GetDomainBoolExpression(memberDomainMap);

            if ((bool)scalar.Value == false)
            {
                // The range of the variable was "inverted". Return a NOT of
                // the expression
                expr = new NotExpr<DomainConstraint<BoolLiteral, Constant>>(expr);
            }
            return expr;
        }

        void ReadClusters() {
            XmlRead();
            while (TokenIs(GeometryToken.Cluster))
                ReadCluster();

            FleshOutClusters();
            var rootClusterSet = new Set<Cluster>();
            foreach (var cluster in stringToClusters.Values.Select(c => c.Cluster))
                if (cluster.ClusterParents == null || !cluster.ClusterParents.Any())
                    rootClusterSet.Insert(cluster);

            if (rootClusterSet.Count == 1)
                _graph.RootCluster = rootClusterSet.First();
            else {
                _graph.RootCluster.AddRangeOfCluster(rootClusterSet);
            }

            if (!XmlReader.IsStartElement())
                ReadEndElement();
        }

 Set<Shape> GetCommonAncestorsAbovePassport(Set<Shape> passport) {
     if (!passport.Any()) return new Set<Shape>();
     var ret = ancestorSets[passport.First()];
     foreach (var shape in passport.Skip(1))
         ret *= ancestorSets[shape];
     return ret;
 }

    static void Main()
    {
        Console.Write("Enter number of elements to read: ");
        string line = Console.ReadLine();
        int N;
        while (!(int.TryParse(line, out N) && N > 0))
        {
            Console.Write("Please enter a positive integer: ");
            line = Console.ReadLine();
        }
        Console.WriteLine();

        int[] numbers = new int[N];
        for (int idx = 0; idx < N; idx++)
        {
            Console.Write("Enter number {0}: ", idx + 1);
            line = Console.ReadLine();
            while (!(int.TryParse(line, out numbers[idx])))
            {
                Console.Write("Please enter an integer: ");
                line = Console.ReadLine();
            }
            Console.WriteLine();
        }

        Console.Write("{" + String.Join(", ", numbers) + "} -> ");

        int majMinOccurs = N / 2 + 1;

        /*Solution 1 - Predicates*/

        List<int> numbersList = numbers.ToList<int>();
        Set<int> numbersSet = new Set<int>();

        numbersSet.AddMany(numbersList);

        try
        {
            int majorant = numbersSet.First(setElement => (numbersList.FindAll(
                listElement => listElement == setElement).Count >= majMinOccurs));
            Console.WriteLine(majorant);
        }
        catch
        {
            Console.WriteLine("No majorant!");
        }

        Console.WriteLine();

        /*Solution 2 - Dictionary*/

        //Dictionary<int, int> occurrences = new Dictionary<int, int>();

        //for (int i = 0; i < N; i++)
        //{
        //    if (!occurrences.Keys.Contains(numbers[i]))
        //    {
        //        occurrences.Add(numbers[i], 1);
        //    }
        //    else
        //    {
        //        occurrences[numbers[i]]++;
        //    }
        //}

        //bool hasMajorant = false;

        //foreach (KeyValuePair<int, int> pair in occurrences)
        //{
        //    if (pair.Value >= majMinOccurs)
        //    {
        //        Console.WriteLine(pair.Key);
        //        hasMajorant = true;
        //        break;
        //    }
        //}

        //if (!hasMajorant)
        //{
        //    Console.WriteLine("No majorant!");
        //}

        //Console.WriteLine();
    }

        void FleshOutSubgraphs() {
            foreach (var subgraphTemlate in subgraphTable.Values) {
                var subgraph = subgraphTemlate.Subgraph;
                foreach (var id in subgraphTemlate.SubgraphIdList)
                    subgraph.AddSubgraph(subgraphTable[id].Subgraph);
                foreach (var id in subgraphTemlate.NodeIdList)
                    subgraph.AddNode(this.graph.FindNode(id));
            }
            var rootSubgraphSet = new Set<Subgraph>();
            foreach (var subgraph in subgraphTable.Values.Select(c => c.Subgraph))
                if (subgraph.ParentSubgraph == null) {
                    rootSubgraphSet.Insert(subgraph);
                    graph.RootSubgraph.AddSubgraph(subgraph);
                }

            if (rootSubgraphSet.Count == 1)
                graph.RootSubgraph = rootSubgraphSet.First();
            else 
                foreach (var subgraph in rootSubgraphSet)
                    graph.RootSubgraph.AddSubgraph(subgraph);
        }