The following Python3 code takes an input list of bytes and prints out their hexadecimal "C style" representation, 12 per line:

def c_array_body_from_bytes(input_bytes):
    """Emit the provided bytes as the body of a C array."""
    lines = ""
    for i in range(0, len(input_bytes), 12):
        lines += "".join(f"0x{b:02x}, " for b in input_bytes[i : i + 12]) + "\n"
    return lines

print(c_array_body_from_bytes(range(64)))

Can this be expressed more tersely as a single return statement that uses a nested comprehension, without requiring the accumulator lines variable? If so, what does it look like?

>Solution :

With a single statement based on combined str.joins:

lines = ''.join(''.join(map("0x{:02x}, ".format, input_bytes[i:i+12])) + '\n'
                for i in range(0, len(input_bytes), 12))

---

0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 
0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 
0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23, 
0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 
0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 
0x3c, 0x3d, 0x3e, 0x3f,