On Wed, 11 Sep 2013 02:24:44 +0000, Dave Angel wrote:
> On 10/9/2013 22:14, Steven D'Aprano wrote:
>
>> On Tue, 10 Sep 2013 14:08:45 -0700, stas poritskiy wrote:
>>
>>> Greetings to all!
>>>
>>> i ran into a little logic problem and trying to figure it out.
>>>
>>> my case is as follows:
>>>
>>> i have a list of items each item represents a Group i need to create a
>>> set of nested groups, so, for example:
>>>
>>> myGroups = ["head", "neck", "arms", "legs"]
>>
>>
>> What is the rule for grouping these items? Below, you suggest:
>>
>> head encloses neck
>> neck encloses arms
>> arms encloses legs
>>
>> which seems rather strange. But if it is *always* the case that each
>> item encloses the next item:
>>
>> def print_nested_list(alist):
>> spaces = ' '*4
>> for level, item in enumerate(alist):
>> if level != 0:
>> indent = spaces*(level-1) + ' '
>> print (indent + '|_>'), # note comma
>> print item
>>
>>
>> which gives us this:
>>
>> py> print_nested_list(['head', 'neck', 'arms', 'legs']) head
>> |_> neck
>> |_> arms
>> |_> legs
>>
>>
>> as requested.
>>
>>
>>
> Very nice. But what I want to know is how did you know that Stan (the
> OP) wanted his printed output to be formatted that way?
I don't. Stan's email is unclear. But he does show an example:
[quote]
so, for example:
myGroups = ["head", "neck", "arms", "legs"]
i need to get them to be represented like this: (if you can imaging a
folder structure)
head
|_> neck
|_> arms
|_>legs
and so on until i hit the last element.
[end quote]
so I just provided that.
> He said:
>
>>>>>> i need to create a set of nested groups,
> and
>>>>>> store each of the first elements of a par, so I can reference to
>>>>>> them as to a parent of another group.
I have no idea what that means :-)
I *guess* that what Stan is actually looking for is something like a
dictionary-based solution, not lists:
{'head': {'neck': {'arms': {}, 'legs': {}}}}
which gives:
head encloses neck
neck encloses arms and legs
arms enclose nothing
legs enclose nothing
or:
{'head': {'neck': {'arms': {'legs': {}}}}}
which gives:
head encloses neck
neck encloses arms
arms encloses legs
legs enclose nothing
but I can't really tell for sure. In this second case, using dicts, I
might try something like this recursive solution:
def print_nested_dict(adict, level=0):
if adict == {}:
return
for key, subdict in sorted(adict.items()):
if level != 0:
spaces = ' '*4
indent = spaces*(level-1) + ' '
print (indent + '|_>'), # note comma
if subdict == {}:
print key
else:
print "%s:-" % key
print_nested_dict(subdict, level+1)
Given:
d = {'head': {'neck': {'legs': {'toes': {}}, 'arms': {'thumbs': {},
'fingers': {}}}}}
we can see this output:
py> print_nested_dict(d)
head:-
|_> neck:-
|_> arms:-
|_> fingers
|_> thumbs
|_> legs:-
|_> toes
--
Steven
--
https://mail.python.org/mailman/listinfo/python-list
