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POProcessing ranking data w/ C# & LINQ
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  1. POProcessing ranking data w/ C# & LINQ
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    copied!<p>I have an object in a list that I need to rank several different ways. Currently the code is rather unwieldy as it requires me to individually address each column. Example:</p> <pre><code>public class Data { public int AValue { get; set; } public int ARanking { get; set; } public int BValue { get; set; } public int BRanking { get; set; } public int CValue { get; set; } public int CRanking { get; set; } } public class Container { public List&lt;Data&gt; RankingData { get; set; } public void RankData() { int count = 1; foreach (Data item in RankingData.OrderBy(d =&gt; d.AValue)) { item.ARanking = count; count++; } count = 1; foreach (Data item in RankingData.OrderBy(d =&gt; d.BValue)) { item.BRanking = count; count++; } count = 1; foreach (Data item in RankingData.OrderBy(d =&gt; d.CValue)) { item.CRanking = count; count++; } } } </code></pre> <p>The problem I am trying to solve is I want to write something roughly like this:</p> <pre><code>public void RankData&lt;V, R&gt;() { int count = 1; foreach(Data item in RankingData.OrderBy(V)) { item.R = count; count++; } } </code></pre> <p>So that as I need to alter the ranking logic (for example, handle tie breaking rules) that I write the code once instead of copying the code 20 times to make the rules match. What am I missing?</p> <p><strong>UPDATE</strong></p> <p>Using Tanzelax's solution as a base this is the extension class I came up with:</p> <pre><code>public static class RankingExtension { public static void SetRanking&lt;TKey&gt;(this List&lt;Data&gt; dataSet, bool Ascending, Func&lt;Data, TKey&gt; getOrderBy, Action&lt;Data, int&gt; setRank) where TKey : IComparable { var ordered = (Ascending) ? dataSet.OrderBy(getOrderBy) : dataSet.OrderByDescending(getOrderBy); int i = 1; foreach (Data item in ordered) { setRank(item, i); i++; } } } </code></pre> <p>I had to add in a switch so that I could control whether or not the field was being sorted ascending or not. And in my test scenarios it produces the appropriate output:</p> <pre><code> List&lt;Data&gt; test = new List&lt;Data&gt;(); test.Add(new Data { AValue = 25, BValue = 1.25, CValue = 99.99 }); test.Add(new Data { AValue = 89, BValue = 2.10, CValue = 1.01 }); test.Add(new Data { AValue = 10, BValue = 6, CValue = 45.45 }); test.Add(new Data { AValue = 15, BValue = 2.33, CValue = 2.99 }); test.Add(new Data { AValue = 90, BValue = 5.43, CValue = 27.89 }); test.SetRanking(false, d =&gt; d.AValue, (d, i) =&gt; d.ARank = i); test.SetRanking(false, d =&gt; d.BValue, (d, i) =&gt; d.BRank = i); test.SetRanking(true, d =&gt; d.CValue, (d, i) =&gt; d.CRank = i); </code></pre>
 

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