Return a subset of Array using index C#

Question

What is the best way to return a subset of a C# array given a fromIndex and toIndex?

Obviously I can use a loop but are there other approaches?

This is the method signature I am looking to fill.

public static FixedSizeList<T> FromExisting(FixedSizeList<T> fixedSizeList, Int32 fromIndex, Int32 toIndex)

FixedSizeList internal implementation is

private T[] _Array;
this._Array = new T[size];

lol, yeah just noticed that myself. Generics hurts my brain... — Maxim Gershkovich
– Maxim Gershkovich, Commented Mar 7, 2011 at 3:04

Bala R · Accepted Answer · 2011-03-07 04:07:07Z

10

myArray.Skip(fromIndex).Take(toIndex - fromIndex + 1);

EDIT: The result of Skip and Take are IEnumerable and the count will be zero until you actually use it.

if you try

        int[] myArray = {1, 2, 3, 4, 5};
        int[] subset = myArray.Skip(2).Take(2).ToArray();

subset will be {3, 4}

edited Mar 7, 2011 at 4:07

answered Mar 7, 2011 at 3:01

Bala R

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4 Comments

Maxim Gershkovich Over a year ago

I actually liked this approach more then all of them but am failing to get it working. Skip() no matter what I pass in returns 0 items... Must be doing something wrong... hmmmm

Bala R Over a year ago

@Maxim you could try adding .ToArray() to the expression.

Maxim Gershkovich Over a year ago

Got ya... Didn't catch on that I was dealing with IEnumerable... Thanks again mate :-)

ariscris Over a year ago

I found that I need the following to make this work: using System.Linq;

Shekhar_Pro · Accepted Answer · 2011-03-07 03:03:24Z

3

List Already has a CopyTo Method which should do what you want.

http://msdn.microsoft.com/en-us/library/3eb2b9x8.aspx

This is the Signature of the method:

public void CopyTo( int index, T[] array, int arrayIndex,   int count )

answered Mar 7, 2011 at 3:03

Shekhar_Pro

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Comments

munificent · Accepted Answer · 2011-03-07 03:05:18Z

3

Array.Copy will do what you want.

answered Mar 7, 2011 at 3:05

munificent

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