Convert Bytes to a String

Convert bytes to a string

Decode the bytes object to produce a string:

>>> b"abcde".decode("utf-8") 
'abcde'

The above example assumes that the bytes object is in UTF-8, because it is a common encoding. However, you should use the encoding your data is actually in!

How do I convert a Python 3 byte-string variable into a regular string?

You had it nearly right in the last line. You want

str(bytes_string, 'utf-8')

because the type of bytes_string is bytes, the same as the type of b'abc'.

Converting Byte to String and Back Properly in Python3?

Note: Some codes found on the Internet.

You could try to convert it to hex format. Then it is easy to convert it back to byte format.

Sample code to convert bytes to string:

hex_str = rnd_bytes.hex()

Here is how 'hex_str' looks like:

'771296b8'

And code for converting it back to bytes:

new_rnd_bytes = bytes.fromhex(hex_str)

The result is:

b'w\x12\x96\xb8'

For processing you can use:

readable_str = ''.join(chr(int(hex_str[i:i+2], 16)) for i in range(0, len(hex_str), 2))

But newer try to encode readable string, here is how readable string looks like:

'w\x12\x96¸'

After processing readable string convert it back to hex format before converting it back to bytes string like:

hex_str = ''.join([str(hex(ord(i)))[2:4] for i in readable_str])

convert a byte array to string

You could convert the byte array to a char array, and then construct a string from that

scala> val bytes = Array[Byte]('a','b','c','d')
bytes: Array[Byte] = Array(97, 98, 99, 100)

scala> (bytes.map(_.toChar)).mkString 
res10: String = abcd

scala> 

How to Convert Byte Array back into string?

If s is that byte string:

for x in s:
    print(f'{x:08b}')

Instead of print, you can do what you like with the strings of 0's and 1's.

It is unnecessarily inefficient to go through strings of 0 and 1 characters for encoding and decoding. You should instead assemble and disassemble the bytes directly using the bit operators (<<, >>, |, &).

How to convert bytes to string in Python 3 to concatenate(serialized_data,signature)

Use .digest() not .hexdigest() to get a byte string that can be prepended to the serialized data byte string. Open the file for binary read/write:

import pickle
import json
import hashlib
import hmac

class User(object):
    def __init__(self, name):
        self.name = name

filename = 'user.file'
KEY = b'secret'

user = User('david')
serialized = pickle.dumps(user)
#calculate the signature
signature = hmac.new(KEY, serialized, hashlib.sha256).digest() # not .hexdigest()

with open(filename, 'wb') as file_object:                 # binary write
    file_object.write(signature + serialized)

with open(filename, 'rb') as file_object:                 # binary read
    raw_data = file_object.read()
    if len(raw_data) >= len(signature):                   # need >= here
        read_signature = raw_data[:len(signature)]
        read_data = raw_data[len(signature):]
        computed_signature = hmac.new(KEY, read_data, hashlib.sha256).digest() # not .hexdigest()
        if hmac.compare_digest(computed_signature, read_signature):
            userDeserialized = pickle.loads(read_data)
            print (userDeserialized.name)

Output:

david

Bytes not the same when converting from bytes to string to bytes

data_str.encode() expects data_str to be the result of data.decode().

str(data) doesn't return a decoded byte string, it returns the printed representation of the byte string, what you would type as a literal in a program. If you want to convert that back to a byte string, use ast.literal_eval().

import ast

with open(r'file-path', 'rb') as file: 
    data = file.read()
    str_data = str(data)
    new_data = ast.literal_eval(str_data)
    print(new_data == data)

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