Bitwise Operations

Chris Angelico rosuav at gmail.com
Tue Jul 30 01:44:19 CEST 2013


On Tue, Jul 30, 2013 at 12:34 AM, Devyn Collier Johnson
<devyncjohnson at gmail.com> wrote:
>
> I understand the symbols. I want to know how to perform the task in a script
> or terminal. I have searched Google, but I never saw a command. Typing "101
> & 010" or "x = (int(101, 2) & int(010, 2))" only gives errors.

Your problem here isn't in the bitwise operators, but in your binary
literals. Python deliberately and consciously rejects 010 as a
literal, because it might be interpreted either as decimal 10, or as
octal (decimal 8), the latter being C's interpretation. Fixing that
shows up a more helpful error:

>>> x = (int(101, 2) & int(10, 2))
Traceback (most recent call last):
  File "<pyshell#74>", line 1, in <module>
    x = (int(101, 2) & int(10, 2))
TypeError: int() can't convert non-string with explicit base

The int() call isn't doing what you think it is, because 101 is
already an int. The obvious solution now is to quote the values:

>>> x = (int("101", 2) & int("010", 2))
>>> x
0

But there's an easier way:

>>> x = 0b101 & 0b010
>>> x
0

I think that might do what you want. Also check out the bin()
function, which will turn an integer into a string of digits.

ChrisA



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