How To Reduce Python Script Memory Usage

Coo Jinx picture Coo Jinx · Jun 12, 2012 · Viewed 40.4k times · Source

I have a very large python script, 200K, that I would like to use as little memory as possible. It looks something like:

# a lot of data structures
r = [34, 78, 43, 12, 99]

# a lot of functions that I use all the time
def func1(word):
    return len(word) + 2

# a lot of functions that I rarely use
def func1(word):
    return len(word) + 2


# my main loop
while 1:
   # lots of code
   # calls functions

If I put the functions that I rarely use in a module, and import them dynamically only if necessary, I can't access the data. That's as far as I've gotten.

I'm new at python.

Can anyone put me on the right path? How can I break this large script down so that it uses less memory? Is it worth putting rarely used code in modules and only calling them when needed?

Answer

cedbeu picture cedbeu · Jun 12, 2012

Organazing:

Your python script seems indeed to be huge, maybe you should consider reorganizing your code first, to split in into several modules or packages. It will probably make easier the code profiling and the optimization tasks.

You may want to have a look there:

And possibly:

Optimizing:

There is a lot of things that can be done for optimizing your code ...

For instance, regarding your data structures ... If you make a big use of lists or lists comprehensions, you could try to figure out where do you really need lists, and where they might be replaced by non-mutable data structures like tuples or by "volatile" objects, "lazy" containers, like generator expressions.

See:

On these pages, you could find some useful information and tips:

Also, you should study your ways for doing things and wonder whether there is a way to do that less greedily, a way that it's better to do it in Python (you will find some tips in the tag pythonic) ... That is especially true in Python, since in Python, there is often one "obvious" way (and only one) to do things which is better than the others (see The Zen of Python), which is said to be pythonic. It's not especially related to the shape of your code, but also - and above all - to the performances. Unlike a lot of languages, which promote the idea that there should be many ways for doing anything, Python prefers to focus on the best way only. So obviously, there are many ways for doing something, but often, one is really better.

Now, you should also verify whether you are using the best methods for doing things, because pythonicality won't arrange your algorithms for you.

But at last, it's very depending on your code it's difficult to answer without having seen it.

And, make sure to take into account the comments made by eumiro and Amr.