Pythonic use of logical operators to verify variable validity

Readable code is usually considered pythonic. While this may seem foreign if Python is a second language, once you understand how the logical, coalescing operators work it becomes quite readable; therefore, I would say this is indeed pythonic.

I've seen this used all over, and prefer to use it myself. The alternative is to nest two assignment operations inside of an if..else. This has always seemed counter-intuitive to me, because you're assigning a value to the same variable, but you must use two assignment operators. This is neither minimalist or readable, and therefore not pythonic.

As a side note, I often find myself missing these operators when I use other languages. I typically explain this behavior with the analogy "like Python's or operator".

result = this_variable and this_variable[0].operation()

What happens if this_variable is empty? you are left with result = [] (assuming it was a list). That makes no sense. Are you interested in the AND operation of these two values? not really, what you really want is the result of this_variable[0].operation(), only that before you need to make sure this_variable is not empty. So a more declarative code (which also has a more sensible result when this_variable is empty), would be:

result = (this_variable[0].operation() if this_variable else None)

result = search or make_something()

Here you want result to be the value search or, if this is falsy, the output of make_something(). So this code is ok, perfectly declarative. You could write it with a conditional expression (as any other boolean expression) but they are usually not as clear.