Navigating a nested dictionary using a deque

Question

I have a dictionary like so:

{
    a: {
        b: {
            c: "Hello World!"
        }
    }
}

And I have a deque like so:

deque(["a", "b", "c"])

I would like to print Hello World! using the two data structures above - how can this be done?

What have you attempted? Is something in particular challenging you? — miradulo, Apr 30 '18 at 03:43
If you have `my_dict = {...}`, you can do `mydict['a']` to index the first level of nesting. — Code-Apprentice, Apr 30 '18 at 03:46
Not deque specific but `functools.reduce(operator.getitem, deq, d)` is a nice way. [Related (possible duplicate) question](https://stackoverflow.com/questions/14692690/access-nested-dictionary-items-via-a-list-of-keys). — miradulo, Apr 30 '18 at 03:54

score 4 · Answer 1 · answered Apr 30 '18 at 03:47

I dont know why you want to this but this may help:

 for i in deque(['a','b','c']):
     d= d[i]
 > d
 Hello World!

It only works if the dict has those keys, you can improve code as much as you can.
one more think is that the dictionary should have keys with ' like 'a'.

user3483203 · Accepted Answer · 2018-04-30T03:58:48.593

2

If x is your dictionary, and y is your deque:

while y:
    x = x[y.popleft()]

x is now:

'Hello World!'

There are easier ways to accomplish this, like as @miradulo mentioned:

functools.reduce(operator.getitem, y, x)

But this makes use of popleft() which is a deque operation.

edited Apr 30 '18 at 03:58

answered Apr 30 '18 at 03:48

user3483203

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This is exactly what I was looking for and it's only 2 lines - thanks a lot. – Ogen Apr 30 '18 at 03:52
1

This also exhausts the deque, so you know you are finished. – user3483203 Apr 30 '18 at 03:53

Navigating a nested dictionary using a deque

2 Answers2