Does "swap A for B" imply a direction?
I am not an English native, so maybe the question is trivial. In case you're confused why I even ask: the German "tauschen" has no direction included.
You shouldn't have both CDs and DVDs, please swap CDs for DVDs.
Is it clear from this statement if you should have only CDs or only DVDs?
Solution 1:
In a lot of examples, commutivity is obvious:
- The two computers can easily swap data.
- We swapped houses during the children's school vacation.
- Do you want to swap places?
- If you prefer to sit next to Chris, I'll swap seats with you.
- When you've finished reading your book, and I've finished mine, can we swap?
- We swapped addresses with the people we met on vacation.
- We spent the evening swapping (= telling each other) stories/jokes.
But one non-commutative sense (swap [A] for [B] = replace [what you have] with [something else]) may be the default as in this specifying definition (though admittedlyin the examples given, it is contextually forced)
swap someting for something: to exchange something you have [or in hypothetical situations would see yourselves having] for something else:
- Most consumers said they wouldn't swap the product [they owned / desired] for a cheaper own-label brand.
- They've swapped their old car for a much larger one.
- When he got a job in a bank, he had to swap his jeans and T-shirt for a suit (= he had to wear formal clothes instead of informal ones).
- [ + two objects ] I'll swap you my chocolate bar for your peanuts.
(All quotes so far from Cambridge Dictionary, re-ordered.)
But as I expected, counterexamples (swap [A] for [B] = replace with [something else] [what you have]) aren't hard to find on the internet:
- "I'll swap you your pasta salad, for this apple", my friend would tell me.
- I'll swap your flat mate for mine ..."
ie 'I'll / I would exchange something else for something I have.'
So 'I'll swap A for B' does not entail that it is A or B that you have. You have (perhaps hypothetically) one of them. Directionality (who is the donor of the first mentioned article / state ... and who the recipient) must be indicated by context, though A is more usually owned by the speaker.