Tip/Trick

How to split an array into multiple arrays

Libish Varghese Jacob

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4.78/5 (6 votes)

6 May 2013CPOL

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How to split an array into different array of size n

Introduction

This tip will help you split an array of size m into multiple arrays of size n.

Using the code

C++

String[] arrayString = new string[]{"","","","",""};
List<string[]> splitted = new List<string[]>();//This list will contain all the splitted arrays.
int lengthToSplit = 3;

int arrayLength = arrayString.Length;

for (int i = 0; i < arrayLength; i = i + lengthToSplit)
{
  string[] val = new string[lengthToSplit];
                
  if (arrayLength < i + lengthToSplit)
     {
        lengthToSplit = arrayLength - i;
     }
  Array.Copy(arrayString, i, val, 0, lengthToSplit);
  splitted.Add(val);
}

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Comments and Discussions

Correcting last array

Member 112126686-Nov-14 6:45

Member 11212668

6-Nov-14 6:45

To give the correct last array, invert the following code

string[] val = new string[lengthToSplit];

 if (arrayLength < i + lengthToSplit)
    {
       lengthToSplit = arrayLength - i;
    }

with

if (arrayLength &lt; i + lengthToSplit)
    {
       lengthToSplit = arrayLength - i;
    }

string[] val = new string[lengthToSplit];

If you not do this, you can obtain the last array with more positions that needed.

Eagle Carvalho

My vote of 5

JayantaChatterjee13-May-13 4:27

JayantaChatterjee

13-May-13 4:27

My Vote of 5.
Thanks for giving this quicker method to implements the Arrays....

simpler solution with linq

rrrado9-May-13 3:07

rrrado

9-May-13 3:07

or simpler

int i = 0;
    arrayString.GroupBy(s => i++/lengthToSplit).Select(g => g.ToArray()).ToList()

Re: simpler solution with linq

densat5-Jan-14 21:10

densat

5-Jan-14 21:10

linq is not supported net framework 2.0

This may be quicker

George Swan6-May-13 19:41

George Swan

6-May-13 19:41

Thanks for the useful example. I think this variation may be quicker because it avoids calling Array.Copy

”c#”

for (int i = 0; i < arrayLength; i++)
               {
                   int arrayIndex = i % lengthToSplit;
                   if (arrayIndex == 0)
                   {
                       if (i != 0)
                       {
                           splitted.Add(val);
                       }
                       val = new string[lengthToSplit];
                   }
                   val[arrayIndex] = arrayString[i];
               }

               splitted.Add(val);

Best wishes.

My vote of 5

Member 418708230-May-12 1:51

Member 4187082

30-May-12 1:51

its very usefull post save my lot of time

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