Binary to String/Text in Python

To convert bits given as a "01"-string (binary digits) into the corresponding text in Python 3:

>>> bits = "0110100001101001"
>>> n = int(bits, 2)
>>> n.to_bytes((n.bit_length() + 7) // 8, 'big').decode()
'hi'

For Python 2/3 solution, see Convert binary to ASCII and vice versa.

It looks like you are trying to decode ASCII characters from a binary string representation (bit string) of each character.

You can take each block of eight characters (a byte), convert that to an integer, and then convert that to a character with chr():

>>> X = "0110100001101001"
>>> print(chr(int(X[:8], 2)))
h
>>> print(chr(int(X[8:], 2)))
i

Assuming that the values encoded in the string are ASCII this will give you the characters. You can generalise it like this:

def decode_binary_string(s):
    return ''.join(chr(int(s[i*8:i*8+8],2)) for i in range(len(s)//8))

>>> decode_binary_string(X)
hi

If you want to keep it in the original encoding you don't need to decode any further. Usually you would convert the incoming string into a Python unicode string and that can be done like this (Python 2):

def decode_binary_string(s, encoding='UTF-8'):
    byte_string = ''.join(chr(int(s[i*8:i*8+8],2)) for i in range(len(s)//8))
    return byte_string.decode(encoding)

In Python 2, an ascii-encoded (byte) string is also a utf8-encoded (byte) string. In Python 3, a (unicode) string must be encoded to utf8-encoded bytes. The decoding example was going the wrong way.

>>> X = "1000100100010110001101000001101010110011001010100"
>>> X.encode()
b'1000100100010110001101000001101010110011001010100'

Strings containing only the digits '0' and '1' are a special case and the same rules apply.