Easy way to switch keys and values in Python dictionary

[Niklas]

Hi!

I use dictionaries for translating texts between languages. They typically look like this:

trans_en_sv = { 'parish': 'socken', 'county': 'län', 'municipality': 'kommun', 'rune stone': 'runsten', 'rock carving': 'hällristning', 'rune inscribed boulder': 'runhäll', 'runic inscription': 'runinskrift' } 

This one is from English to Swedish. If I want to use the same dictionary for translating the other way, is there a smarter way than looping through it and create a new dictionary? I have a feeling there should be some way to just flip around the keys and values on the fly. 🤔

Best regards, Niklas

[ccc]

flipped = {value: key for key, value in trans_en_sv.items()} # dict comprehension

[Niklas]

Thanks! That looked even easier than I had anticipated. 😀 I love Python.

[mikael]

@Niklas, ”why can’t I reverse lookup a dict?” Is probably something every Python coder has asked at one point, but the language has no such concept.

If you have a largish dict with lot of additions and reverse lookups, you might not want to reverse the whole dict every time, in which case something like this might be useful.