How can I extract the bit representation of a byte value in Go?

Extracting Bit Representations from Bytes in Go

When manipulating byte values in Go, it's often necessary to work with individual bits. This article explores methods for extracting bit representations from bytes, addressing the specific challenge of determining the bit representation for the byte value 1.

Bit Representation

To visually represent the bits in a byte, you can use fmt.Sprintf("b", ...), as suggested by others. However, for mathematical operations involving bits, bitwise operators are essential.

To determine the n^th bit of a byte, perform a bitwise AND operation (&) between the byte and a byte with the n^th bit set to 1 (mask). This mask is calculated as 2^n-1.

Example: Calculating the 1st Bit

To find the 1st bit of the number 13 (00001101), mask it with 2⁰ = 1 (00000001):

fmt.Print(13 & 1) // Output: 1

The result is 1, indicating that the 1st bit is 1.

Hamming Distance Function

The Hamming distance between two bytes measures the number of different bits. Here is a function that calculates the Hamming distance between two byte arrays (single-byte arrays in the given scenario):

func hamming(a, b []byte) (int, error) {
    if len(a) != len(b) {
        return 0, errors.New("a b are not the same length")
    }

    diff := 0
    for i := 0; i < len(a); i++ {
        b1 := a[i]
        b2 := b[i]
        for j := 0; j < 8; j++ {
            mask := byte(1 << uint(j))
            if (b1 & mask) != (b2 & mask) {
                diff++
            }
        }
    }
    return diff, nil
}

This function uses bitwise AND operations to compare corresponding bits of the byte arrays. The Go Playground demonstrates its usage:

https://play.golang.org/p/O1EGdzDYAn

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