<s>[INST] How do you express binary literals in Python? How do you express an integer as a binary number with Python literals?
I was easily able to find the answer for hex:
    >>> 0x12AF
    4783
    >>> 0x100
    256

and octal:
    >>> 01267
    695
    >>> 0100
    64

How do you use literals to express binary in Python?

Summary of Answers

Python 2.5 and earlier: can express binary using int('01010101111',2) but not with a literal.
Python 2.5 and earlier: there is no way to express binary literals.
Python 2.6 beta: You can do like so: 0b1100111 or 0B1100111.
Python 2.6 beta: will also allow 0o27 or 0O27 (second character is the letter O) to represent an octal.
Python 3.0 beta: Same as 2.6, but will no longer allow the older 027 syntax for octals.

 [/INST] For reference—future Python possibilities:
Starting with Python 2.6 you can express binary literals using the prefix 0b or 0B:
>>> 0b101111
47

You can also use the new bin function to get the binary representation of a number:
>>> bin(173)
'0b10101101'

Development version of the documentation: What's New in Python 2.6
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