Why are you using version 2.5? That’s pretty out of date.

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You're familiar with lists? It functions very similarly to a list. Like you can read from the documentaion, there's some optimization reason why the data structure is selected to be a deque instead of list, but from usage perspective they're quite identical.

An empty list vs. deque would be:

a_list = []
a_deque = collections.deque()

Initialized to some starting values instead of being empty:

a_list = [1,2,3]
a_deque = collections.deque([1,2,3])

And a way to initialize same value several times is to say [a_value]*n for example [1]*3 would be same as [1,1,1]. So finally the differences for that type of initialization:

a_list = [0.0]*buffer_size
a_deque = collections.deque([0.0]*buffer_size)

And then the only last difference to the actual code is that they also set a maximum length of the deque object so it can't ever hold more values than that.

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Ig pop(0) from a list has O(n) time complexity whereas in deque it's O(1) approx More on reddit.com

Yes. So first off, make sure you know what a collection is. You've probably used most of the basic ones. Forget the collections module for now. Collections are containers. They are well named because they "collect" multiple items together. The most basic containers don't need to be imported: list, tuple, set and dict. Let's look at list: # typically you would create a list like this: l_1 = [] l_1.append(4) # but this is also a perfectly acceptable way to create a list: l_2 = list() l_2.append(1) You see how that second way sort of looks like how you'd create any other object from it's class? The collections module is filled with specialised collections. Most of them build on those basic containers but add extra functions or behaviours that might be useful for you. Some of them are less useful in modern versions of python than they were in older versions of python. I'd say you probably don't need to know the collections module as a beginner. Most beginner stuff can be achieved with the standard collections. The collections in collections are quite well named, and if you can't immediately see what they might be used for, then that is okay - you don't have to use them! Using them might actually be over complicating things for now. Let's start with collections.OrderedDict, which is an extension on the standard dict. In old python (below 3.7), the order in which you add keys to the dict is NOT necessarily the order they are stored in, so when you loop through my_dict.items(), the keys could be in a different order every time. If you used an OrderedDict, the order in which you add keys is preserved. You don't have to worry about this one so much if you're using 3.7 or above - because standard dicts preserve the order of keys after Python3.7. (There are actually some subtle differences between OrderedDict and standard dicts, but they are not so important). There is no collections.UnorderedDict btw. collections.namedtuple is like a tuple that uses names to access it's inner variables, instead of numbers. It's not too dissimilar to what defining a class does, except you can't define methods for a namedtuple. Lets say you wanted to create a class that basically acts like a dict, or a string, or a list, but has some custom functionality, perhaps a new method like you wanted to add. In old python, you can't inherit from list, you had to inherit from UserList. There are still reasons to inherit from UserList in new python instead of lists, but they are beyond beginner. A lot of this module is beyond beginner. collections.Counter is an extension on the standard dict that will count up identical keys for you. collections.deque is a double ended queue. This is a very standard data structure in computer science. Queues are very much like a queue in real life, the first item in is the last item to come out. You might not need to use it so much in python just yet. The official python docs look scary, but if you read them in detail you will get a more complete picture of what these are used for, and what capabilities they have. https://docs.python.org/3/library/collections.html More on reddit.com