How can you assign multiple inputs a single value in Python dictionaries?

Question

I would like to assign countries a currency value, but some currencies are used in multiple countries. I know I can just assign them individually for every country but is there a better way of doing it? Something I tried was:

rates = { ('England', 'wales'): 'GBP' }

where the expected result was:

rates['England'] = GBP
rates['wales'] = GBP

This doesn't work though. What can I do?

`rates = {'England': 'GBP', 'Wales': 'GBP'}` is the correct way to do it. — zvone, Oct 17 '20 at 10:12

score 4 · Answer 1 · answered Oct 17 '20 at 10:15

There isn't any syntactic sugar for that use case, but you could use a few methods that aren't too verbose to get the same result:

fromkeys

# first argument are all keys, second is default value (or None)
rates = dict.fromkeys(('England', 'wales'), 'GBP')

comprehension

rates = {k: 'GBP' for k in ('England', 'wales')}

score 0 · Answer 2 · answered Oct 17 '20 at 10:13

0

You could perhaps just flip the two?

rates = { 
"GBP": ["England", "Wales"], 
"EUR": ["Germany", "Fance", "Netherlands"] 
}

answered Oct 17 '20 at 10:13

Toby_TheBlock

81
3

score 0 · Answer 3 · answered Oct 17 '20 at 10:16

0

You can create lists of countries and add them all in one loop:

GBP_countries=['England', 'wales']
rates = {}
for country in  GBP_countries:
    rates.update({country:'GBP'})

answered Oct 17 '20 at 10:16

flabons

331
1
8

Why use `update` with a singleton `dict`? Just bind the key. – user2390182 Oct 17 '20 at 10:16

How can you assign multiple inputs a single value in Python dictionaries?

3 Answers3

fromkeys

comprehension