Convert int to a bit array in .NET

Question

How can I convert an int to a bit array?

If I e.g. have an int with the value 3 I want an array, that has the length 8 and that looks like this:

0 0 0 0 0 0 1 1 

Each of these numbers are in a separate slot in the array that have the size 8.

Answer 1

Use the BitArray class.

int value = 3; BitArray b = new BitArray(new int[] { value }); 

If you want to get an array for the bits, you can use the BitArray.CopyTo method with a bool[] array.

bool[] bits = new bool[b.Count]; b.CopyTo(bits, 0); 

Note that the bits will be stored from least significant to most significant, so you may wish to use Array.Reverse.

And finally, if you want get 0s and 1s for each bit instead of booleans (I'm using a byte to store each bit; less wasteful than an int):

byte[] bitValues = bits.Select(bit => (byte)(bit ? 1 : 0)).ToArray(); 

Answer 2

To convert the int 'x'

int x = 3; 

One way, by manipulation on the int :

string s = Convert.ToString(x, 2); //Convert to binary in a string  int[] bits= s.PadLeft(8, '0') // Add 0's from left              .Select(c => int.Parse(c.ToString())) // convert each char to int              .ToArray(); // Convert IEnumerable from select to Array 

Alternatively, by using the BitArray class-

BitArray b = new BitArray(new byte[] { x }); int[] bits = b.Cast<bool>().Select(bit => bit ? 1 : 0).ToArray();