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Re: Retrieve item deep in dict tree?

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On 04/02/2014 01:18 PM, Steven D'Aprano wrote:
> 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)

+1

Short, simple -- good Python.  :)

--
~Ethan~

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Thread

Retrieve item deep in dict tree? Roy Smith <roy@panix.com> - 2014-04-02 13:58 -0400
  Re: Retrieve item deep in dict tree? John Gordon <gordon@panix.com> - 2014-04-02 18:03 +0000
  Re: Retrieve item deep in dict tree? Steven D'Aprano <steve@pearwood.info> - 2014-04-02 20:18 +0000
    Re: Retrieve item deep in dict tree? Ethan Furman <ethan@stoneleaf.us> - 2014-04-02 13:25 -0700
  Re: Retrieve item deep in dict tree? Rustom Mody <rustompmody@gmail.com> - 2014-04-02 19:41 -0700
    Re: Retrieve item deep in dict tree? Rustom Mody <rustompmody@gmail.com> - 2014-04-02 21:15 -0700
      Re: Retrieve item deep in dict tree? Steven D'Aprano <steve@pearwood.info> - 2014-04-03 05:29 +0000
      Re: Retrieve item deep in dict tree? Ian Kelly <ian.g.kelly@gmail.com> - 2014-04-03 01:00 -0600

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