How to use the dictionary function?

Question

I have the dictionary

d = {'a':3, 'b':7, 'c':8}

I was wondering how could i reverse the order of the dictionary in order to make it look like this:

d = {3:'a', 7:'b', 8:'c'}

I would like to do this without just writing it like this. Is there a way i can use the first dict in order to obtain the new result?

It is not sorting. Just reversing keys and values. at first I, too, misunderstood — mshsayem, Apr 04 '13 at 05:29
Don't use `dict` as a variable name, python builtin dictionary class is already called `dict` — jamylak, Apr 04 '13 at 05:42
i changed it, as you can see below the builtin `dict` has been used, this is the type of interference we are trying to avoid — jamylak, Apr 04 '13 at 06:04

score 12 · Answer 1 · answered Apr 04 '13 at 05:25

12

Yes. You can call items on the dictionary to get a list of pairs of (key, value). Then you can reverse the tuples and pass the new list into dict:

transposed = dict((value, key) for (key, value) in my_dict.items())

Python 2.7 and 3.x also have dictionary comprehensions, which make it nicer:

transposed = {value: key for (key, value) in my_dict.items()}

answered Apr 04 '13 at 05:25

icktoofay

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dict comps exist in 2.7+, not just 3.x – Gareth Latty Apr 04 '13 at 05:26

score 1 · Answer 2 · answered Apr 04 '13 at 06:08

1

transposed = dict(zip(d.values(), d))

answered Apr 04 '13 at 06:08

John La Rooy

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How to use the dictionary function?

2 Answers2