Optional variables in Python

Question

do you guys know if there exists a Python equivalent to boost::optional in C++ (or std::optional since C++11: http://en.cppreference.com/w/cpp/utility/optional), i.e. a library that handles semantically optional variables?

I know how to implement it myself or use the other solutions (like foo = (bar, True) which I find ugly and unreadable). Just curious if there is an existing solution.

Answer 1

Optional variables, a limited form of algebraic typing, are primarily useful in statically typed languages. In dynamically typed languages like Python, there's no real need for them. As arshajii said, you can use None (or, if you prefer, any other sentinel you'd like) to represent an absent value. You then just check whether the variable has the expected type or not.