Python Cache: How to Speed Up Your Code with Effective Caching

This blog was initially posted to Crawlbase Blog

Efficient and fast code is important for creating a great user experience in software applications. Users don’t like waiting for slow responses, whether it’s loading a webpage, training a machine learning model, or running a script. One way to speed up your code is caching.

The purpose of caching is to temporarily cache frequently used data so that your program may access it more rapidly without having to recalculate or retrieve it several times. Caching can speed up response times, reduce load, and improve user experience.

This blog will cover caching principles, its role, use cases, strategies and real world examples of caching in Python. Let’s get started!

Implementing Caching in Python

Caching can be done in Python in multiple ways. Let’s look at two common methods: using a manual decorator for caching and Python’s built-in functools.lru_cache.

1. Manual Decorator for Caching

A decorator is a function that wraps around another function. We can create a caching decorator that stores the result of function calls in memory and returns the cached result if the same input is called again. Here's an example:

import requests

# Manual caching decorator
def memoize(func):
    cache = {}
    def wrapper(*args):
        if args in cache:
            return cache[args]
        result = func(*args)
        cache[args] = result
        return result
    return wrapper

# Function to get data from a URL
@memoize
def get_html(url):
    response = requests.get(url)
    return response.text

# Example usage
print(get_html('https://crawlbase.com'))

In this example, the first time get_html is called, it fetches the data from the URL and caches it. On subsequent calls with the same URL, the cached result is returned.

1. Using Python’s functools.lru_cache

Python provides a built-in caching mechanism called lru_cache from the functools module. This decorator caches function calls and removes the least recently used items when the cache is full. Here's how to use it:

from functools import lru_cache

@lru_cache(maxsize=128)
def expensive_computation(x, y):
    return x * y

# Example usage
print(expensive_computation(5, 6))

In this example, lru_cache caches the result of expensive_computation. If the function is called again with the same arguments, it returns the cached result instead of recalculating.

Performance Comparison of Caching Strategies

When choosing a caching strategy, you need to consider how they perform under different conditions. Caching strategies performance depends on the number of cache hits (when data is found in the cache) and the size of the cache.

Here’s a comparison of common caching strategies:

Choosing the right caching strategy depends on your application’s data access patterns and performance needs.

Final Thoughts

Caching can be very useful for your apps. It can reduce data retrieval time and system load. Whether you’re building a web app, a machine learning project or want to speed up your system, smart caching can make your code run faster.

Caching methods such as FIFO, LRU and LFU have different use cases. For example, LRU is good for web apps that need to keep frequently accessed data, whereas LFU is good for programs that need to store data over time.

Implementing caching correctly will let you design faster, more efficient apps and get better performance and user experience.