thing.md

Say thing can be one of foo, bar, baz, or quux. Additionally, self has methods foo, bar, baz and quux. This is ok:

if thing == 'foo':
    self.foo()

and this is fine:

if thing != 'quux':
    getattr(self, thing)()

The things in the middle are murky. I myself would not consistently choose one way over the other. I might sometimes write

if thing == 'foo':
    self.foo()
elif thing == 'bar':
    self.bar()

and others write

if thing in ['foo', 'bar']:
    getattr(self, thing)()

depending on how I expect the code to grow, more than anything else. To reach three branches, in my own code, would be rare, but I probably wouldn't flag it for review. I would flag four.

If things were more complicated (20 different values of thing, 10 of them needing an action, say), I might

• create a class,

class throwaway(C):
    notwanted1 = notwanted2 = notwanted3 = lambda _: None

(assuming type(self)==C)

• use a dict,

d = {'foo': C.foo, 'bar': C.bar, 'baz': C.baz, ...}
d.get(thing, lambda _: None)(self)

again, depending.

Lastly,

class C:
    def foo(self):
        pass
    foo.do_thing = True

    def bar(self):
        pass
    bar.do_thing = False
    
    # etc

so then,

method = getattr(self, thing)
if method.do_thing:
    method()