Convert binary to ASCII and vice versa

Question

Using this code to take a string and convert it to binary:

bin(reduce(lambda x, y: 256*x+y, (ord(c) for c in 'hello'), 0)) 

this outputs:

0b110100001100101011011000110110001101111 

Which, if I put it into this site (on the right hand site) I get my message of hello back. I'm wondering what method it uses. I know I could splice apart the string of binary into 8's and then match it to the corresponding value to bin(ord(character)) or some other way. Really looking for something simpler.

Answer 1

For ASCII characters in the range [ -~] on Python 2:

>>> import binascii >>> bin(int(binascii.hexlify('hello'), 16)) '0b110100001100101011011000110110001101111' 

In reverse:

>>> n = int('0b110100001100101011011000110110001101111', 2) >>> binascii.unhexlify('%x' % n) 'hello' 

---

In Python 3.2+:

>>> bin(int.from_bytes('hello'.encode(), 'big')) '0b110100001100101011011000110110001101111' 

In reverse:

>>> n = int('0b110100001100101011011000110110001101111', 2) >>> n.to_bytes((n.bit_length() + 7) // 8, 'big').decode() 'hello' 

---

To support all Unicode characters in Python 3:

def text_to_bits(text, encoding='utf-8', errors='surrogatepass'):     bits = bin(int.from_bytes(text.encode(encoding, errors), 'big'))[2:]     return bits.zfill(8 * ((len(bits) + 7) // 8))  def text_from_bits(bits, encoding='utf-8', errors='surrogatepass'):     n = int(bits, 2)     return n.to_bytes((n.bit_length() + 7) // 8, 'big').decode(encoding, errors) or '\0' 

Here's single-source Python 2/3 compatible version:

import binascii  def text_to_bits(text, encoding='utf-8', errors='surrogatepass'):     bits = bin(int(binascii.hexlify(text.encode(encoding, errors)), 16))[2:]     return bits.zfill(8 * ((len(bits) + 7) // 8))  def text_from_bits(bits, encoding='utf-8', errors='surrogatepass'):     n = int(bits, 2)     return int2bytes(n).decode(encoding, errors)  def int2bytes(i):     hex_string = '%x' % i     n = len(hex_string)     return binascii.unhexlify(hex_string.zfill(n + (n & 1))) 

Example

>>> text_to_bits('hello') '0110100001100101011011000110110001101111' >>> text_from_bits('110100001100101011011000110110001101111') == u'hello' True