jedierikb jedierikb - 9 days ago 6
Python Question

efficient circular buffer?

I want to create an efficient circular buffer in python (with the goal of taking averages of the integer values in the buffer).

Is this an efficient way to use a list to collect values?

def add_to_buffer( self, num ):
self.mylist.pop( 0 )
self.mylist.append( num )


What would be more efficient (and why)?

Answer

I would use collections.deque with a maxlen arg

>>> import collections
>>> d = collections.deque(maxlen=10)
>>> d
deque([], maxlen=10)
>>> for i in xrange(20):
...     d.append(i)
... 
>>> d
deque([10, 11, 12, 13, 14, 15, 16, 17, 18, 19], maxlen=10)

There is a recipe in the docs for deque that is similar to what you want. My assertion that it's the most efficient rests entirely on the fact that it's implemented in C by an incredibly skilled crew that is in the habit of cranking out top notch code.

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