LINQ之Any

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Any(）

Any()可以判断序列是否为空。 MSDN public static bool Any( this IEnumerable source );

代码示例：

public static class Program
{
    static void Main( string[] args )
    {
        int[]   numbersA = new int[] { };
        int[]   numbersB = new int[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };

        bool reaultA = numbersA.Any();
        bool reaultB = numbersB.Any();

        System.Console.WriteLine( "numbersA:{0}", numbersA.Text() );
        System.Console.WriteLine( "numbersB:{0}", numbersB.Text() );
        System.Console.WriteLine( "numbersA是否有元素:{0}", reaultA );
        System.Console.WriteLine( "numbersB是否有元素:{0}", reaultB );
        
        System.Console.ReadKey();
    }

    public static string Text( this IEnumerable i_source )
    {
        string text = string.Empty;
        foreach( var value in i_source )
        {
            text += string.Format( "[{0}], ", value );
        }
        return text;
    }
} 

numbersA:
numbersB:[0], [1], [2], [3], [4], [5], [6], [7], [8], [9],
numbersA是否有元素:False
numbersB是否有元素:True

还可以用于检查是否有满足条件的元素。 MSDN public static bool Any( this IEnumerable source, Func predicate );

以下示例描述了使用lambda表达式的条件语句。

代码示例：

public static class Program
{
    static void Main( string[] args )
    {
        int[]   numbers = new int[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };

        bool reaultA = numbers.Any( value => value % 2 == 0 );
        bool reaultB = numbers.Any( value => value >= 10 );
        bool reaultC = numbers.Any( value => value