Bitwise operation on Binary string python

Question

If I have two strings of binary representation. How to do bitwise on them?

Example

a = '101'
b = '010'
c = a | b
c => '111'

• khelwood: 1. Parse them as ints (in binary). 2. Perform | operation. 3. Convert result to string. (4. Profit.)
• Tomerikoo: Does this answer your question? bitwise operation on string representation of binary number python 2.7
• Tomerikoo: stackoverflow.com/questions/48373554/…
• khelwood: Does this answer your question? Logical OR for Bit-string in Python

Answer 1

First, use int to convert the binary strings to numbers. You can use the second parameter of int to specify the base, 2 in this case. Then, you can use | to "or" the numbers and bin or a format-string (many different possibilities here) to convert back to binary.

>>> a = '101'
>>> b = '010'
>>> c = int(a, 2) | int(b, 2)
>>> bin(c)
'0b111'
>>> f"{c:b}"
'111'
>>> format(c, "b")
'111'

The latter two can also be used to add any number of leading zeros, if necessary, e.g. using 08b instead of b in the format string.

• tobias_k: @AnirbanNag'tintinmj' Then you are using an older version of Python. Use the ones that do not give an error.
• Kelly Bundy: Removes leading zeros, though, for example '010' and '001' turn into '11' instead of '011'.

Answer 2

A solution that works on the strings (not via ints) and keeps leading zeros intact:

>>> a = '0101'
>>> b = '0011'
>>> ''.join(map(max, a, b))
'0111'

Needs the strings to have equal length, but given your example where one string has a leading zero so it's as long as the other, I guess that's the case for you.

• tobias_k: Neat... but you might add a note that both strings have to be the same length.
• Kelly Bundy: Hmm, since the OP's example is '101' and '010', not '10', I believe their strings do have the same length.