I think this is the kind of thing you just have to learn when you use any language. But when you're switching between half a dozen, being able to rely on consistent founding design principles really makes things easier. And when there aren't any, this kind of guide helps.
I really like Python's design here, if we are not talking about full on language features to enforce immutability, where functions that mutate never return a value and are named with verbs (e.g. 'sort()'), while functions that don't mutate return their value and are named with adjectives (e.g. 'sorted()'). This feels natural - mutations are actions, while pure functions are descriptions.
The only real downside is the lack of return values mean you can't chain mutations, but personally that never bothered me.
i used to like that distinction as well but verbs are too useful to let mutating stuff use them all up! and pure functions are actions as well, they just result in a new thing. also, some verbs sound awkward adjectified: take, drop, show, go, get ...
I think this is the kind of thing you just have to learn when you use any language. But when you're switching between half a dozen, being able to rely on consistent founding design principles really makes things easier. And when there aren't any, this kind of guide helps.