How To Reduce Python Script Memory Usage
module, optimization, organization, package, python
Solution
Organizing:
Your python script seems indeed to be huge, maybe you should consider reorganizing your code first, to split it 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:
- Python Project Howto
- Python Packages
- SO: Organising my Python project
And possibly:
- SO: Python: What is the common header format?
- How do you organize Python modules?
- The Hitchiker's Guide to Packaging
Optimizing:
There is a lot of things that can be done for optimizing your code ...
For instance, regarding your data structures ... If you make 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:
- SO: Are tuples more efficient than lists in Python?
- SO: Generator Expressions vs. List Comprehension
- PEP 255 - Simple Generators and PEP 289 - Generator Expressions
On these pages, you could find some useful information and tips:
- http://wiki.python.org/moin/PythonSpeed
- http://wiki.python.org/moin/PythonSpeed/PerformanceTips
- http://wiki.python.org/moin/TimeComplexity
- http://scipy.org/PerformancePython
Also, you should study your ways of 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 are 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 many languages, which promote the idea that there should be many ways to do 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 varies depending on your code and it's difficult to answer without having seen it.
And, make sure to take into account the comments made by eumiro and Amr.
Problem
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?
Related problems
- What is the common header format of Python files?
- How can I check the memory usage of objects in iPython?
- Generator expressions vs. list comprehensions
- Organising my Python project
- Which Python memory profiler is recommended?
- Are tuples more efficient than lists in Python?
- How do you organize Python modules?