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    <p>You can't really randomize a Enumerable unless you convert it to an array first, because an enumerator by definition gets 1 value at a time, token by token. </p> <p>So, if I understand correctly, I would do something like this...</p> <ol> <li>Convert list_of_is to an array</li> <li>For each j in list_of_js</li> <li>Loop through list_of_is performing Fisher-Yates shuffle</li> <li>Loop through list_of_is and do f(j,i) where i is the current index in the shuffle</li> </ol> <p>Here's a quick example, I hope this helps (sorry fixed some errors)</p> <pre><code>using System; using System.Collections.Generic; using System.Diagnostics; using System.Linq; namespace ConsoleApplication1 { class Program { static IEnumerable&lt;char&gt; list_of_is = new char[] {'a', 'b', 'c', 'd', 'e', 'f', 'g'}; static IEnumerable&lt;char&gt; list_of_js = new char[] { 'x', 'y', 'z' }; static void Main(string[] args) { foreach (string result in Randomize()) Debug.Write(result); } public static IEnumerable&lt;String&gt; Randomize() { char[] random_is = list_of_is.ToArray(); int jCount = list_of_js.Count(); Random r = new Random(); // foreach j foreach(char j in list_of_js) { // create a random ordering of is for (int i = random_is.Length - 1; i &gt;= 0; i--) { int x = r.Next(0, i); // swap char temp = random_is[x]; random_is[x] = random_is[i]; random_is[i] = temp; } // now evaluate the random pairs foreach(Char i in random_is) yield return String.Format("{0}{1} ", Char.ToUpper(i), j); } } } } </code></pre> <p>outputs</p> <pre><code>Gx Cx Ex Bx Fx Ax Dx Dy By Fy Ay Cy Gy Ey Bz Az Gz Cz Fz Ez Dz </code></pre> <p><strong>Edit:</strong> Actually, it just hit me that your pseudocode doesn't quite seem right. You are generating 3 random arrays of 7 values.. and then wanting to output pairs of X,Y,Z for each of the random arrays. It seems like yoou would need 3 * 7 * 3 = 63 ouputs then..</p> <p>Therefore, this may be more accurate:</p> <pre><code>public static IEnumerable&lt;String&gt; Randomize() { char[] random_is = list_of_is.ToArray(); int jCount = list_of_js.Count(); Random r = new Random(); // foreach j for (int random = 0; random &lt; jCount; random++) { // create a random ordering of is for (int i = random_is.Length - 1; i &gt;= 0; i--) { int x = r.Next(0, i); // swap char temp = random_is[x]; random_is[x] = random_is[i]; random_is[i] = temp; } // now evaluate the random pairs foreach (Char i in random_is) foreach(Char j in list_of_js) yield return String.Format("{0}{1} ", Char.ToUpper(i), j); } } </code></pre> <p>And it outputs:</p> <pre><code>Cx Cy Cz Gx Gy Gz Dx Dy Dz Bx By Bz Fx Fy Fz Ax Ay Az Ex Ey Ez Bx By Bz Cx Cy Cz Fx Fy Fz Ax Ay Az Ex Ey Ez Dx Dy Dz Gx Gy Gz Cx Cy Cz Ax Ay Az Bx By Bz Gx Gy Gz Fx Fy Fz Ex Ey Ez Dx Dy Dz </code></pre>
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    1. POTest i Enumerables Randomly, j Times in Order
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    1. COThanks but the solution uses the same random array with each x,y,z pair. The main issue is being able to generate x,y,z pairs using different random permutations
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    2. COWhat now? How is that different?
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    3. COBecause all x,y,z's process the same random list. The difference is that each x,y,z should process the same list in a different random order.
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