How to Print Bytes as Hexadecimal

Byte Array to Hex String

Using str.format:

>>> array_alpha = [ 133, 53, 234, 241 ]
>>> print ''.join('{:02x}'.format(x) for x in array_alpha)

or using format

>>> print ''.join(format(x, '02x') for x in array_alpha)

Note: In the format statements, the 02 means it will pad with up to 2 leading 0s if necessary. This is important since [0x1, 0x1, 0x1] i.e. (0x010101) would be formatted to "111" instead of "010101"

or using bytearray with binascii.hexlify:

>>> import binascii
>>> binascii.hexlify(bytearray(array_alpha))

Here is a benchmark of above methods in Python 3.6.1:

from timeit import timeit
import binascii

number = 10000

def using_str_format() -> str:
return "".join("{:02x}".format(x) for x in test_obj)

def using_format() -> str:
return "".join(format(x, "02x") for x in test_obj)

def using_hexlify() -> str:
return binascii.hexlify(bytearray(test_obj)).decode('ascii')

def do_test():
print("Testing with {}-byte {}:".format(len(test_obj), test_obj.__class__.__name__))
if using_str_format() != using_format() != using_hexlify():
raise RuntimeError("Results are not the same")

print("Using str.format -> " + str(timeit(using_str_format, number=number)))
print("Using format -> " + str(timeit(using_format, number=number)))
print("Using binascii.hexlify -> " + str(timeit(using_hexlify, number=number)))

test_obj = bytes([i for i in range(255)])

test_obj = bytearray([i for i in range(255)])


Testing with 255-byte bytes:
Using str.format -> 1.459474583090427
Using format -> 1.5809937679100738
Using binascii.hexlify -> 0.014521426401399307
Testing with 255-byte bytearray:
Using str.format -> 1.443447684109402
Using format -> 1.5608712609513171
Using binascii.hexlify -> 0.014114164661833684

Methods using format do provide additional formatting options, as example separating numbers with spaces " ".join, commas ", ".join, upper-case printing "{:02X}".format(x)/format(x, "02X"), etc., but at a cost of great performance impact.

How do I print bytes as hexadecimal?

Well you can convert one byte (unsigned char) at a time into a array like so

char buffer [17];
buffer[16] = 0;
for(j = 0; j < 8; j++)
sprintf(&buffer[2*j], "%02X", data[j]);

Print bytes to hex

The Python repr can't be changed. If you want to do something like this, you'd need to do it yourself; bytes objects are trying to minimize spew, not format output for you.

If you want to print it like that, you can do:

from itertools import repeat

hexstring = '7403073845'

# Makes the individual \x## strings using iter reuse trick to pair up
# hex characters, and prefixing with \x as it goes
escapecodes = map(''.join, zip(repeat(r'\x'), *[iter(hexstring)]*2))

# Print them all with quotes around them (or omit the quotes, your choice)
print("'", *escapecodes, "'", sep='')

Output is exactly as you requested:


How to convert a byte array to a hex string in Java?

From the discussion here, and especially this answer, this is the function I currently use:

private static final char[] HEX_ARRAY = "0123456789ABCDEF".toCharArray();
public static String bytesToHex(byte[] bytes) {
char[] hexChars = new char[bytes.length * 2];
for (int j = 0; j < bytes.length; j++) {
int v = bytes[j] & 0xFF;
hexChars[j * 2] = HEX_ARRAY[v >>> 4];
hexChars[j * 2 + 1] = HEX_ARRAY[v & 0x0F];
return new String(hexChars);

My own tiny benchmarks (a million bytes a thousand times, 256 bytes 10 million times) showed it to be much faster than any other alternative, about half the time on long arrays. Compared to the answer I took it from, switching to bitwise ops --- as suggested in the discussion --- cut about 20% off of the time for long arrays. (Edit: When I say it's faster than the alternatives, I mean the alternative code offered in the discussions. Performance is equivalent to Commons Codec, which uses very similar code.)

2k20 version, with respect to Java 9 compact strings:

private static final byte[] HEX_ARRAY = "0123456789ABCDEF".getBytes(StandardCharsets.US_ASCII);
public static String bytesToHex(byte[] bytes) {
byte[] hexChars = new byte[bytes.length * 2];
for (int j = 0; j < bytes.length; j++) {
int v = bytes[j] & 0xFF;
hexChars[j * 2] = HEX_ARRAY[v >>> 4];
hexChars[j * 2 + 1] = HEX_ARRAY[v & 0x0F];
return new String(hexChars, StandardCharsets.UTF_8);

What's the correct way to convert bytes to a hex string in Python 3?

Since Python 3.5 this is finally no longer awkward:

>>> b'\xde\xad\xbe\xef'.hex()

and reverse:

>>> bytes.fromhex('deadbeef')

works also with the mutable bytearray type.


How to print byte array in hexadecimal - c++ [duplicate]

Use printf function:

printf("%x", bytes[0]);

See here if you want to know more about printf function.

How do you convert a byte array to a hexadecimal string in C?

printf("%02X:%02X:%02X:%02X", buf[0], buf[1], buf[2], buf[3]);

For a more generic way:

int i;
for (i = 0; i < x; i++)
if (i > 0) printf(":");
printf("%02X", buf[i]);

To concatenate to a string, there are a few ways you can do this. I'd probably keep a pointer to the end of the string and use sprintf. You should also keep track of the size of the array to make sure it doesn't get larger than the space allocated:

int i;
char* buf2 = stringbuf;
char* endofbuf = stringbuf + sizeof(stringbuf);
for (i = 0; i < x; i++)
/* i use 5 here since we are going to add at most
3 chars, need a space for the end '\n' and need
a null terminator */
if (buf2 + 5 < endofbuf)
if (i > 0)
buf2 += sprintf(buf2, ":");
buf2 += sprintf(buf2, "%02X", buf[i]);
buf2 += sprintf(buf2, "\n");

view bytes as hex values only (do not decode characters)

You might use binascii.hexlify if you are happy with just hex digits (no \x)

import binascii
x = b"\x61"



Byte array to Hex string conversion in javascript

You are missing the padding in the hex conversion. You'll want to use

function toHexString(byteArray) {
return Array.from(byteArray, function(byte) {
return ('0' + (byte & 0xFF).toString(16)).slice(-2);

so that each byte transforms to exactly two hex digits. Your expected output would be 04812d7e3a9829e5d51bdd64ceb35df060699bc1309731bd6e6f1a5443a7f9ce0af4382fcfd6f5f8a08bb2619709c2d49fb771601770f2c267985af2754e1f8cf9

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