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copied!<p><strike> It's ok but I'd prefer a simpler syntax :</p> <pre><code>double[] x = { 2, 3, 1, 5, 7, 2, 3 }; double[] y = { 2, 3, 1, 5, 7, 2, 3 }; double[] x_sorted = x.OrderBy(d => d).ToArray(); double[] y_sorted = y.OrderBy(d => d).ToArray(); </code></pre> <p></strike></p> <p><strong>Edit:</strong></p> <p>Argh... I failed to spot that this was an associative array sort.</p> <pre><code>double[] x = { 2, 3, 1, 5, 7, 2, 3 }; double[] y = { 1, 2, 3, 4, 5, 6, 7 }; double[] y_sorted = y.Clone() as double[]; double[] x_sorted = x.Clone() as double[]; Array.Sort(x_sorted, y_sorted); </code></pre> <p><strong>Edit 2 1/2</strong></p> <p>And some performance tests :</p> <pre><code>public class Program { delegate void SortMethod(double[] x, double[] y); private const int ARRAY_SIZE = 3000000; private static Random RandomNumberGenerator = new Random(); private static double[] x = GenerateTestData(ARRAY_SIZE); private static double[] y = GenerateTestData(ARRAY_SIZE); private static double[] GenerateTestData(int count) { var data = new double[count]; for (var i = 0; i < count; i++) { data[i] = RandomNumberGenerator.NextDouble(); } return data; } private static void SortMethod1(double[] x, double[] y) { Array.Sort(x, y); } private static void SortMethod2(double[] x, double[] y) { IEnumerable<int> range = Enumerable.Range(0, x.Length); x = (from n in range orderby x[n] select y[n]).ToArray(); y = (from n in range orderby x[n] select x[n]).ToArray(); } private static void SortMethod3(double[] x, double[] y) { int[] x_index = Enumerable.Range(0, x.Length).OrderBy(i => x[i]).ToArray(); x = x_index.Select(i => x[i]).ToArray(); y = x_index.Select(i => y[i]).ToArray(); } private static void SortMethod4(double[] x, double[] y) { int[] range = Enumerable.Range(0, x.Length).OrderBy(i => x[i]).ToArray(); var q = ( from n in range orderby x[n] select new { First = x[n], Second = y[n] }).ToArray(); x = q.Select(t => t.First).ToArray(); y = q.Select(t => t.Second).ToArray(); } private static void SortMethodPerformanceTest(SortMethod sortMethod) { double[] y_sorted = y.Clone() as double[]; double[] x_sorted = x.Clone() as double[]; var sw = new Stopwatch(); sw.Start(); sortMethod.Invoke(x_sorted, y_sorted); sw.Stop(); Console.WriteLine( string.Format( "{0} : {1}", sortMethod.Method.Name, sw.Elapsed)); } static void Main(string[] args) { Console.WriteLine("For array length : " + ARRAY_SIZE); Console.WriteLine("------------------------------"); SortMethodPerformanceTest(SortMethod1); SortMethodPerformanceTest(SortMethod2); SortMethodPerformanceTest(SortMethod3); SortMethodPerformanceTest(SortMethod4); Console.WriteLine("Press any key to continue..."); Console.ReadKey(); } } </code></pre> <p>And the results : </p> <pre> For array length : 3000000 ------------------------------ SortMethod1 : 00:00:00.6088503 // Array.Sort(Array, Array) SortMethod2 : 00:00:07.9583779 // Original SortMethod3 : 00:00:04.5023336 // dtb's Linq Alternative SortMethod4 : 00:00:06.6115911 // Christian's Linq Alternative </pre>

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