If by binary you mean bytes type, you can just use encode method of the string object that encodes your string as a bytes object using the passed encoding type. You just need to make sure you pass a proper encoding to encode function.

In [9]: "hello world".encode('ascii')                                                                                                                                                                       
Out[9]: b'hello world'

In [10]: byte_obj = "hello world".encode('ascii')                                                                                                                                                           

In [11]: byte_obj                                                                                                                                                                                           
Out[11]: b'hello world'

In [12]: byte_obj[0]                                                                                                                                                                                        
Out[12]: 104

Otherwise, if you want them in form of zeros and ones --binary representation-- as a more pythonic way you can first convert your string to byte array then use bin function within map :

>>> st = "hello world"
>>> map(bin,bytearray(st))
['0b1101000', '0b1100101', '0b1101100', '0b1101100', '0b1101111', '0b100000', '0b1110111', '0b1101111', '0b1110010', '0b1101100', '0b1100100']
 

Or you can join it:

>>> ' '.join(map(bin,bytearray(st)))
'0b1101000 0b1100101 0b1101100 0b1101100 0b1101111 0b100000 0b1110111 0b1101111 0b1110010 0b1101100 0b1100100'

Note that in python3 you need to specify an encoding for bytearray function :

>>> ' '.join(map(bin,bytearray(st,'utf8')))
'0b1101000 0b1100101 0b1101100 0b1101100 0b1101111 0b100000 0b1110111 0b1101111 0b1110010 0b1101100 0b1100100'

You can also use binascii module in python 2:

>>> import binascii
>>> bin(int(binascii.hexlify(st),16))
'0b110100001100101011011000110110001101111001000000111011101101111011100100110110001100100'

hexlify return the hexadecimal representation of the binary data then you can convert to int by specifying 16 as its base then convert it to binary with bin.

If you're looking for bin() as an equivalent to hex(), it was added in python 2.6.

Example:

>>> bin(10)
'0b1010'

If the answer from falsetru didn't work you could also try:

>>> b'a string'.decode('utf-8')
'a string'