Shortest Way to Shuffle Array
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/*I am trying to find the absolute shortest way to shuffle the following array. I saw many different methods on the MSDN and Google Search, but no one show a short method of completley (ramdom, no order) shuffling an array.*/
int\[\] array = {1,2,3,4,5}; for (int i = 0; i < 5; i++) Console.WriteLine("{0}", array\[i\]); -
/*I am trying to find the absolute shortest way to shuffle the following array. I saw many different methods on the MSDN and Google Search, but no one show a short method of completley (ramdom, no order) shuffling an array.*/
int\[\] array = {1,2,3,4,5}; for (int i = 0; i < 5; i++) Console.WriteLine("{0}", array\[i\]);I prefer to use a Generic method to handle sorting any Type:
private T[] ShuffleArray<T>(T[] theArray)
{
Random rnd = new Random((int) DateTime.Now.Ticks & 0x0000FFFF);
return theArray.OrderBy(itm => rnd.Next()).ToArray();
}Examples of use:
int[] theInts = new int[]{1,2,3,4,5};
theInts = ShuffleArray(theInts);
string[] theStrings = new string[] {"a", "b", "c", "d","e","f"};
theStrings = ShuffleArray(theStrings);
I used the code in this 2008 StackOverFlow thread for the shuffling routine shown here, but adapted it myself to be generic: [^]. I strongly suggest you study that SO thread; it has a variety of techniques presented, and good discussion of issues. The technique I'm using here is not as "powerful," and fast, as other techniques: your specific Application may need/require stronger methods, including, possibly, the use of the Cryptographic Random generator in .NET; see: [^] for an example that uses 'OrderBy with the Cryptographic Random generator.
“The best hope is that one of these days the Ground will get disgusted enough just to walk away ~ leaving people with nothing more to stand ON than what they have so bloody well stood FOR up to now.” Kenneth Patchen, Poet
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/*I am trying to find the absolute shortest way to shuffle the following array. I saw many different methods on the MSDN and Google Search, but no one show a short method of completley (ramdom, no order) shuffling an array.*/
int\[\] array = {1,2,3,4,5}; for (int i = 0; i < 5; i++) Console.WriteLine("{0}", array\[i\]);You might want to check the Computerphile channel on youtube who do a number of very good presentations on sorting arrays(I take it when you say shuffle you mean sort). The short answer is that there is no fastest method that fits all scenarios - depending on the number of elements and distribution different methods will be faster or slower. The main factor influencing which sort algorithm to use is the size of the array.
“That which can be asserted without evidence, can be dismissed without evidence.”
― Christopher Hitchens
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You might want to check the Computerphile channel on youtube who do a number of very good presentations on sorting arrays(I take it when you say shuffle you mean sort). The short answer is that there is no fastest method that fits all scenarios - depending on the number of elements and distribution different methods will be faster or slower. The main factor influencing which sort algorithm to use is the size of the array.
“That which can be asserted without evidence, can be dismissed without evidence.”
― Christopher Hitchens
The use of the word "random" indicates the question is, indeed, about shuffling, not sorting.
“The best hope is that one of these days the Ground will get disgusted enough just to walk away ~ leaving people with nothing more to stand ON than what they have so bloody well stood FOR up to now.” Kenneth Patchen, Poet
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I prefer to use a Generic method to handle sorting any Type:
private T[] ShuffleArray<T>(T[] theArray)
{
Random rnd = new Random((int) DateTime.Now.Ticks & 0x0000FFFF);
return theArray.OrderBy(itm => rnd.Next()).ToArray();
}Examples of use:
int[] theInts = new int[]{1,2,3,4,5};
theInts = ShuffleArray(theInts);
string[] theStrings = new string[] {"a", "b", "c", "d","e","f"};
theStrings = ShuffleArray(theStrings);
I used the code in this 2008 StackOverFlow thread for the shuffling routine shown here, but adapted it myself to be generic: [^]. I strongly suggest you study that SO thread; it has a variety of techniques presented, and good discussion of issues. The technique I'm using here is not as "powerful," and fast, as other techniques: your specific Application may need/require stronger methods, including, possibly, the use of the Cryptographic Random generator in .NET; see: [^] for an example that uses 'OrderBy with the Cryptographic Random generator.
“The best hope is that one of these days the Ground will get disgusted enough just to walk away ~ leaving people with nothing more to stand ON than what they have so bloody well stood FOR up to now.” Kenneth Patchen, Poet
Interesting link provided
Every day, thousands of innocent plants are killed by vegetarians. Help end the violence EAT BACON
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I prefer to use a Generic method to handle sorting any Type:
private T[] ShuffleArray<T>(T[] theArray)
{
Random rnd = new Random((int) DateTime.Now.Ticks & 0x0000FFFF);
return theArray.OrderBy(itm => rnd.Next()).ToArray();
}Examples of use:
int[] theInts = new int[]{1,2,3,4,5};
theInts = ShuffleArray(theInts);
string[] theStrings = new string[] {"a", "b", "c", "d","e","f"};
theStrings = ShuffleArray(theStrings);
I used the code in this 2008 StackOverFlow thread for the shuffling routine shown here, but adapted it myself to be generic: [^]. I strongly suggest you study that SO thread; it has a variety of techniques presented, and good discussion of issues. The technique I'm using here is not as "powerful," and fast, as other techniques: your specific Application may need/require stronger methods, including, possibly, the use of the Cryptographic Random generator in .NET; see: [^] for an example that uses 'OrderBy with the Cryptographic Random generator.
“The best hope is that one of these days the Ground will get disgusted enough just to walk away ~ leaving people with nothing more to stand ON than what they have so bloody well stood FOR up to now.” Kenneth Patchen, Poet
Your solution doesn't really help me. I want to shuffle the contents INSIDE the array. So when I index array[0], the value at index array[0] should always be different.
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Interesting link provided
Every day, thousands of innocent plants are killed by vegetarians. Help end the violence EAT BACON
This is a very very funny. But it doesn't help me. lol..
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You might want to check the Computerphile channel on youtube who do a number of very good presentations on sorting arrays(I take it when you say shuffle you mean sort). The short answer is that there is no fastest method that fits all scenarios - depending on the number of elements and distribution different methods will be faster or slower. The main factor influencing which sort algorithm to use is the size of the array.
“That which can be asserted without evidence, can be dismissed without evidence.”
― Christopher Hitchens
I don't want to sort. I want to shuffle (mixed up, disorganize).
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This is a very very funny. But it doesn't help me. lol..
I replied to Bill stating that it was a good link as I personally found it a good read and some of the links inside are also worth reading Bill also showed you a good method of shuffling the array.
Every day, thousands of innocent plants are killed by vegetarians. Help end the violence EAT BACON
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I replied to Bill stating that it was a good link as I personally found it a good read and some of the links inside are also worth reading Bill also showed you a good method of shuffling the array.
Every day, thousands of innocent plants are killed by vegetarians. Help end the violence EAT BACON
I don't understand his example. I have been playing with it all morning. I am very new to this and I am trying to learn. I simply want to move the around the contents randomly.
int[] array = {1,2,3,4,5};
for (int i = 0; i < 5; i++)
Console.WriteLine("{0}", array[i]); -
I don't understand his example. I have been playing with it all morning. I am very new to this and I am trying to learn. I simply want to move the around the contents randomly.
int[] array = {1,2,3,4,5};
for (int i = 0; i < 5; i++)
Console.WriteLine("{0}", array[i]);//Create out array
int[] arrayValues = {1,2,3,4,5,6};//Create a random value
Random rnd = new Random((int)DateTime.Now.Ticks & 0x0000FFFF);//Do the Shuffle, using Linq which returns an object of IEnumerable in this case
// so we need to convert to back to an array hence to ".ToArray()" at the end.
arrayValues = arrayValue.Orderby(itm => rnd.Next()).ToArray();have a read of these, as the solution covers a range of topics but does what you are after. I am afraid to say that you are going to have do some background reading to get yourself up to speed. datetime.now.ticks[^] LINQ Tutorial for Beginners[^]
Every day, thousands of innocent plants are killed by vegetarians. Help end the violence EAT BACON
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/*I am trying to find the absolute shortest way to shuffle the following array. I saw many different methods on the MSDN and Google Search, but no one show a short method of completley (ramdom, no order) shuffling an array.*/
int\[\] array = {1,2,3,4,5}; for (int i = 0; i < 5; i++) Console.WriteLine("{0}", array\[i\]);When you express a problem, it's helpful to think in terms of what you are actually trying to solve. So, when you say the shortest way, this could mean many different things. Do you mean that, given an arbitrarily large array, you want the fastest shuffle? Should it be the fewest number of lines? Any of a half dozen other possible meanings of shortest? You will get a lot of guesses and assumptions about what the problem is that you are trying to solve - especially when you show a code snippet that doesn't have any real relation to the problem other than it's got an array in it.
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I prefer to use a Generic method to handle sorting any Type:
private T[] ShuffleArray<T>(T[] theArray)
{
Random rnd = new Random((int) DateTime.Now.Ticks & 0x0000FFFF);
return theArray.OrderBy(itm => rnd.Next()).ToArray();
}Examples of use:
int[] theInts = new int[]{1,2,3,4,5};
theInts = ShuffleArray(theInts);
string[] theStrings = new string[] {"a", "b", "c", "d","e","f"};
theStrings = ShuffleArray(theStrings);
I used the code in this 2008 StackOverFlow thread for the shuffling routine shown here, but adapted it myself to be generic: [^]. I strongly suggest you study that SO thread; it has a variety of techniques presented, and good discussion of issues. The technique I'm using here is not as "powerful," and fast, as other techniques: your specific Application may need/require stronger methods, including, possibly, the use of the Cryptographic Random generator in .NET; see: [^] for an example that uses 'OrderBy with the Cryptographic Random generator.
“The best hope is that one of these days the Ground will get disgusted enough just to walk away ~ leaving people with nothing more to stand ON than what they have so bloody well stood FOR up to now.” Kenneth Patchen, Poet
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/*I am trying to find the absolute shortest way to shuffle the following array. I saw many different methods on the MSDN and Google Search, but no one show a short method of completley (ramdom, no order) shuffling an array.*/
int\[\] array = {1,2,3,4,5}; for (int i = 0; i < 5; i++) Console.WriteLine("{0}", array\[i\]);This generic function provides a quick way of randomly shuffling (reordering) the items in-place in an existing array:
public static void ShuffleArray(T[] array)
{
Random rnd = new Random();
int[] order = new int[array.Length];
for (int i = 0; i < array.Length; i++)
{
order[i] = rnd.Next();
}
Array.Sort(order, array);
}It can we rewritten as
Random rnd = new Random();
Array.Sort(array.Select(r => rnd.Next()).ToArray(), array);giving just slightly worse performance. According to my tests the use of Array.Sort is about three times faster than the OrderBy solution for a million integer array.
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/*I am trying to find the absolute shortest way to shuffle the following array. I saw many different methods on the MSDN and Google Search, but no one show a short method of completley (ramdom, no order) shuffling an array.*/
int\[\] array = {1,2,3,4,5}; for (int i = 0; i < 5; i++) Console.WriteLine("{0}", array\[i\]);Hi again, using the Fisher-Yates shuffling algorithm [^] seems to be superior in performance:
public static void Shuffle(T[] array)
{
Random rnd = new Random();
for (int i = array.Length - 1; i >= 0; i--)
{
int index = rnd.Next(i);
T temp = array[index];
array[index] = array[i];
array[i] = temp;
}
}