第459页 | Learning Python | 阅读 ‧ 电子书库

Timing Iteration Alternatives

We’ve met quite a few iteration alternatives in this book. To summarize, let’s work through a larger case study that pulls together some of the things we’ve learned about iteration and functions.

I’ve mentioned a few times that list comprehensions have a speed performance advantage over for loop statements, and that map performance can be better or worse depending on call patterns. The generator expressions of the prior sections tend to be slightly slower than list comprehensions, though they minimize memory space requirements.

All that’s true today, but relative performance can vary over time because Python’s internals are constantly being changed and optimized. If you want to verify their performance for yourself, you need to time these alternatives on your own computer and your own version of Python.