Retrieve item deep in dict tree?

[Steven D'Aprano]

On Wed, 02 Apr 2014 13:58:16 -0400, Roy Smith wrote:

> I have a big hairy data structure which is a tree of nested dicts.  I
> have a sequence of strings which represents a path through the tree. 
> Different leaves in the tree will be at different depths (which range
> from 1 to about 4 or 5 at most).  I want to get the value stored at that
> path.  Thus, if
> 
> keys = ['foo', 'bar', 'baz']
> 
> I want to retrieve tree['foo']['bar']['baz'].
> 
> Is there some idiomatic, non-cryptic way to write that as a one-liner?

Er, idiomatic one liner? No, not really. But a helper function makes 
nearly anything into a one-liner:

def traverse(tree, *keys):
    t = tree
    for k in keys:
        t = t[k]
    return t

# one-liner
leaf = traverse(tree, *list_of_keys)


-- 
Steven