Question

Apparently

METHOD 1

if var in ['string one', 'string two']:
    do_something()

is more Pythonic than:

METHOD 2

if var == 'stringone' or var == 'stringtwo':
    dosomething()

Why is Method 1 considered more Pythonic than Method 2?

Answer 1

To be Pythonic is to use the Python constructs and datastructures with clean, readable idioms.

From: What is Pythonic?

Simply put, the first is easier to read than the second – it has less boilerplate, and less overhead than the first. Any Python programmer can look at the first and see that there’s a list of things being checked against, and it reads much more like plain English than the second. Consider if you expanded the list of things being checked against – the first example would read like:

if var in ['string one', 'string two', 'string three']:
    # If var is one of string one, string two, or string three.
    do_something()

while the second would sound like:

if var == 'stringone' or var == 'stringtwo' or var == stringthree:
    # If var is equal to stringone, or var is equal to stringtwo, or var is equal to stringthree.
    dosomething()