convert binary string to integer array in c#

Question

I want to convert binary value into integer array in c#.

For example consider binary value : 111 , it's integer equivalent is 7 (right most digit equals to integer 1, middle binary digit is equivalent to integer 2 and left most digit is 4, so 1+2+4 = 7).

how do I get each integer digit (i.e. 1, 2 ,4) in form of an array (or list) using c# ?

Can you rephrase your question.. ? Do you simply want the binary places? Or do you want the value 7 from the binary representation .. ? Provide some pseudo-code or something so we can see what you're after. — Simon Whitehead, Jan 04 '14 at 23:20
Why would you not just want the integer, and extract bits from that as required? — Jon Skeet, Jan 04 '14 at 23:21
possible duplicate of [Convert binary string into integer](http://stackoverflow.com/questions/9149728/convert-binary-string-into-integer) — Robert Rouhani, Jan 05 '14 at 08:10

bas · Answer 1 · 2014-01-05T09:47:27.790

3

Like this:

string binaryString = "111";
var integerValue = Convert.ToInt64(binaryString,2);

integerValue will be 7 now.

Update, thanks to the comments:

If you want to store each value then you need to go through the string step by step in a for loop and bit-shift (<< operator) to get to your desired outcome.

[Test]
public void BinaryStringToValues()
{
    const string binaryString = "111";
    var values = new List<int>();
    for (var i = 0; i < binaryString.Length; i++)
    {
        if (binaryString[binaryString.Length - i - 1] == '0')
        {
            continue;
        }
        values.Add(1 << i);
    }

    Assert.AreEqual(1, values[0]);
    Assert.AreEqual(2, values[1]);
    Assert.AreEqual(4, values[2]);
}

The test will pass.

edited Jan 05 '14 at 09:47

answered Jan 04 '14 at 23:22

bas

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1

While this answers converting from binary .. I don't know how it relates to "how do I get each integer digit (i.e. 1, 2 ,4)".. or what that even means. – Simon Whitehead Jan 04 '14 at 23:23
Why do I have the feeling I am doing somebodies homework? :) – bas Jan 04 '14 at 23:31
1

Probably because only a teacher would dream up an exercise as silly as this one... or you've simply been trolled. Either way, have a +1 – NotMe Jan 04 '14 at 23:37
If you like, you can use `1 << i` instead of `(int)Math.Pow(2, i)`. – Jeppe Stig Nielsen Jan 04 '14 at 23:53
@JeppeStigNielsen :)), now I have the feeling I am back in university! Thx, looks much cooler this way! :) long time I used bit shifting – bas Jan 05 '14 at 09:46

EZI · Accepted Answer · 2014-01-04T23:57:40.467

3

string bin = "1011";

var str = String.Join(",", bin.Reverse().Select((c, i) => (c - '0') * (1 << i)));

str will be 1,2,0,8. if you want the result as a list

var list = bin.Reverse().Select((c, i) => (c - '0') * (1 << i)).ToList();

edited Jan 04 '14 at 23:57

answered Jan 04 '14 at 23:35

EZI

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@LB If you still want long, use `1L << i`. Or maybe `ulong`, use `1ul`. This will give strange results if string length exceeds 31, or 63, or 64 (`1ul`), so you might want to check for that. – Jeppe Stig Nielsen Jan 05 '14 at 00:01
1

@JeppeStigNielsen How about `((BigInteger)1 << i)` to make it unlimited(!) ? – L.B Jan 05 '14 at 00:07
@L.B Yeah, that is great. – Jeppe Stig Nielsen Jan 05 '14 at 00:18

score 2 · Answer 3 · answered Jan 04 '14 at 23:34

It's not entirely clear what you want, but let's assume that from this string:

"1011011"

you want to get this array:

64, 16, 8, 2, 1

then you can use this code (LINQPad program):

void Main()
{
    string input = "1011011";

    int[] values = input
        .Select((value, idx) => value == '1'
                ? (1 << (input.Length - idx - 1))
                : 0)
        .Where(value => value > 0)
        .ToArray();

    values.Dump();
}

Output:

linqpad output

This will:

For each character that is '1'
Calculate the position, from the right, where the rightmost position is position 0
Then it will calculate 1 << x (x is that position), which will return 1 for the rightmost position, 2 for the one left of it, 4 for the one left of 2, 8 for the next, 16, 32, 64, and so on.
The array at this point would be [64, 0, 16, 8, 0, 2, 1] so we'll remove the zeroes

Thanks everyone, your feedbacks are very helpful.. – Pinal Dave Jan 04 '14 at 23:42 — Pinal Dave, Jan 04 '14 at 23:42

convert binary string to integer array in c#

3 Answers3