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exercism fetch python simple-linked-list

Simple Linked List

Write a simple linked list implementation that uses Elements and a List.

The linked list is a fundamental data structure in computer science, often used in the implementation of other data structures. They're pervasive in functional programming languages, such as Clojure, Erlang, or Haskell, but far less common in imperative languages such as Ruby or Python.

The simplest kind of linked list is a singly linked list. Each element in the list contains data and a "next" field pointing to the next element in the list of elements.

This variant of linked lists is often used to represent sequences or push-down stacks (also called a LIFO stack; Last In, First Out).

As a first take, lets create a singly linked list to contain the range (1..10), and provide functions to reverse a linked list and convert to and from arrays.

When implementing this in a language with built-in linked lists, implement your own abstract data type.

Hints

To support list(), see implementing an iterator for a class.

Additionally, note that Python2's next() has been replaced by __next__() in Python3. For dual compatibility, next() can be implemented as:

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def next(self):
    return self.__next__()

Exception messages

Sometimes it is necessary to raise an exception. When you do this, you should include a meaningful error message to indicate what the source of the error is. This makes your code more readable and helps significantly with debugging. Not every exercise will require you to raise an exception, but for those that do, the tests will only pass if you include a message.

To raise a message with an exception, just write it as an argument to the exception type. For example, instead of raise Exception, you shold write:

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raise Exception("Meaningful message indicating the source of the error")

Submitting Exercises

Note that, when trying to submit an exercise, make sure the solution is in the $EXERCISM_WORKSPACE/python/simple-linked-list directory.

You can find your Exercism workspace by running exercism debug and looking for the line that starts with Workspace.

For more detailed information about running tests, code style and linting, please see the help page.

Source

Inspired by 'Data Structures and Algorithms with Object-Oriented Design Patterns in Ruby', singly linked-lists. http://www.brpreiss.com/books/opus8/html/page96.html#SECTION004300000000000000000

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.