converting string into binary integer in Python

Question

I'm trying to convert a string into a binary integer:

string = "0b011" 
i = int(string)

But this code raises a ValueError. However, the following code works fine:

i = int(0b011)

But here I've passed a binary literal, not a string. How do I convert a string?

Answer 1

Try this code:

string = '0b011'
i = int(string, 2) # value of i is 3

It uses the built-in procedure int() with the optional base parameter, which indicates the base to be used in the conversion - two in this case, from the documentation:

The base parameter gives the base for the conversion (which is 10 by default) and may be any integer in the range [2, 36], or zero. If base is zero, the proper radix is determined based on the contents of string; the interpretation is the same as for integer literals.

Answer 2

use the second optional argument(base), to tell int() that the string is of base 2:

int(str[,base])

>>> string = "0b011"
>>> int(string,2)
3

Answer 3

>>> from ast import literal_eval
>>> literal_eval("0b011")
3