Python list of lists from enum

Question

here is my example

class MyClass(Enum):
    x=[1,3,5]
    y=[2,5,7]
    w=[33,49]

I would like to write method that will give me a list of ALL lists from enum. For that example it should return

[[1,3,5], [2,5,7], [33,49]]

I tried something like this:

listWithValues= [ z.value for z in MyClass]

But as you can guess it didnt work. Thanks for any helpful advices.

One of the issues you're going to run into is that the attributes in a class are stored in a dictionary and don't come out in any specific order. — kindall, Mar 20 '17 at 19:43
maybe listWithValues= [ x.value for x in MyClass] that is wrong example, I mean I would like to have list with EVERY list from enum — Mateusz, Mar 20 '17 at 19:44
@Mateusz Can you please edit into your question what exactly "_list with EVERY list from enum_" is? Like the particular list? — miradulo, Mar 20 '17 at 19:45
@kindall I think may not be an issue with the way the iterator protocol is defined for `Enum` classes (or I guess, metaclasses). In any event, `MyClass.__members__` should return an ordered mapping. — juanpa.arrivillaga, Mar 20 '17 at 19:46
looks like a duplicate of http://stackoverflow.com/questions/952914/making-a-flat-list-out-of-list-of-lists-in-python?rq=1 — Corley Brigman, Mar 20 '17 at 19:47
What's __wrong__ with your output, from the provided list comprehension you put in your question? — miradulo, Mar 20 '17 at 19:48
@Mateusz no, it isn't, because running *your exact code* is giving the output you say you want. So what output are you getting? — juanpa.arrivillaga, Mar 20 '17 at 19:48
@kindall in fact, it is [documented](https://docs.python.org/3/library/enum.html#creating-an-enum) that "Enumerations support iteration, in definition order". — juanpa.arrivillaga, Mar 20 '17 at 19:50
Ok my mistake. I create that listWithValues= [ z.value for z in MyClass] inside class. Outside calss it is working, however I think it is rather not ellegant to store that outside class — Mateusz, Mar 20 '17 at 20:10
@Mateusz It should hypothetically even work inside the class. You _really_ need to add the __actual error message or problem__ you are having in place of "its not working". — miradulo, Mar 20 '17 at 20:13

score 1 · Answer 1 · answered Mar 21 '17 at 08:09

Here is a full example of what you want. This method will always return every list in the enumeration and ignore every other variable.

import enum


class MyClass(enum.Enum):
    x = [1, 2, 3]
    y = [4, 5, 6]
    z = "I am not a list"
    w = ["But", "I", "Am"]

    @classmethod
    def get_lists(cls):
        """ Returns all the lists in the Enumeration"""
        new_list = []

        for potential_list in vars(cls).values():  # search for all of MyClass' attributes
            if (isinstance(potential_list, cls)  # filter out the garbage attributes
                    and isinstance(potential_list.value, list)  # only get the list attributes
                    and len(potential_list.value) != 0):  # only get the non-empty lists

                new_list.append(potential_list.value)

        return new_list


print(MyClass.get_lists())

score 0 · Answer 2 · answered Mar 20 '17 at 21:49

From the comments it sounds like you want a method on the class that will return a list of all the values. Try this:

    @classmethod
    def all_values(cls):
        return [m.value for m in cls]

and in use:

>>> MyClass.all_values()
[[1, 3, 5], [2, 5, 7], [33, 49]]

Python list of lists from enum

2 Answers2