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Best practices for loop efficiency in a Python data processing pipeline

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python best-practices loops Python

I'm working on a project and hit a roadblock. I'm relatively new to this, so bear with me. During code review for our data processing pipeline, I've come across some inefficient loop implementations that could be optimized. The pipeline is built using Python 3.11 and operates on large datasets, so performance is crucial. For instance, one of my colleagues used a nested loop to filter and transform data, and it raised a red flag for me. Here's a snippet of the current implementation: ```python results = [] for item in data: for transformation in transformations: if condition(item, transformation): results.append(apply_transformation(item, transformation)) ``` This approach seems to be quite computationally intense, especially with larger datasets. I attempted to refactor it using list comprehensions to streamline the process: ```python results = [apply_transformation(item, transformation) for item in data for transformation in transformations if condition(item, transformation)] ``` While this definitely looks cleaner, I’m uncertain if it’s actually more efficient in terms of time complexity. Furthermore, I considered using the `map` function along with filter logic, but it seems less readable, and I’m concerned about maintainability: ```python results = list(map(lambda item: apply_transformation(item), filter(lambda item: any(condition(item, t) for t in transformations), data))) ``` What I'm really trying to nail down is whether focusing on readability, even with a potential performance cost, is a better practice in team settings compared to optimizing for speed at the cost of clarity. Any insights on how to balance these factors or alternative strategies for improving loop efficiency would be highly appreciated. Additionally, if there are any common pitfalls I should be aware of when using these constructs, that would be really helpful. Thanks in advance! This is part of a larger service I'm building. Any help would be greatly appreciated! My development environment is Linux.