slow code in Python

[Edgar458g]

Hi everyone.
I’m new to Python and ran into a small problem.
I wrote a script that works fine with small files, but when the file gets bigger, everything becomes very slow. No errors, just takes a long time to finish.
Is this usually about loops or reading the file line by line?
What is the first thing I should check to make it faster?

Thanks in advance.

[sophiasmith]

Hi! Slow Python scripts with big files are usually caused by inefficient loops or reading/processing line by line. First, check how you handle the file and avoid repeated heavy operations. Using efficient data structures and profiling your code with cProfile can help find the bottleneck.

Infinite Craft

[scaredsteal]

First, use a profiler (cProfile) to pinpoint which code is slow instead of guessing.
Then, check how the file is read—read line by line instead of loading the entire file into memory.
Next, see if there are any heavy operations within the loop (such as string manipulation, searching, or regex).
Finally, check the algorithm (avoid nested loops or searching through large lists; use sets/dicts instead). retro bowl

[asimi]

Hi geometry dash lite, Reading a file line by line is actually often better for large files because it uses less memory. The problem is usually what happens inside the loop.

A good first step is to identify:

1. Which part of the script takes the most time
2. How often it runs
3. Whether the same work is repeated unnecessarily

[matrixalex]

Inefficient loops or reading/processing line by line are the usual culprits when it comes to slow Python scripts with large files. Before anything else, make sure you're not doing any hefty operations on the file too often. One way to identify the bottleneck is to use efficient data structures and profile your code using cProfile.
driving directions

[matrixalex]

Inefficient loops or reading/processing line by line are the usual culprits when it comes to slow Python scripts with large files. Before anything else, make sure you're not doing any hefty operations on the file too often. One way to identify the bottleneck is to use efficient data structures and profile your code using cProfile.