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Comment by pharmakom | Hacker News Reader

I don’t always know how fast will be fast enough when I start a project and the risk of needing a rewrite really puts me off Python.

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This is premature optimization right

It's not always the sin it's made out to be. It's a matter of risk and cost. If there's a high risk performance will be an issue, and optimising later will have a high cost (or optimising early has a low cost), then it makes sense.

Yes and no. One of the biggest disadvantages of python is that the way people typically optimize python code is to 1. rewrite in numpy 2. rewrite in Cython (or other python compiler) 3. rewrite in C++

The problem with this workflow is that it means you end up rewriting large chunks of your code over several years in systems that have fairly different idioms. If you suspect you might in the future be performance bottle-necked, writing your code in a faster (but still productive) language to start can be a lot better because you can then improve performance more incrementally without multiple full rewrites.

I think the idea is to rewrite only the hot part in c++. If there isn't a small hot part, then yes python is a poor choice.

I don’t believe so. Choosing a language that is faster (and still productive) from the get-go has almost no cost but reduces the risk of rewrite.

I work in python all the time, and I’ve still not found a situation where this happened. Sometimes you might have specific components that you might want to write in other languages, but this is really rare unless you’re manually writing really computationally intensive or time critical procedures. Which hopefully you should know going into the project. Like if you’re rolling your own in-line audio processing you know up front that python is a bad choice. But any CRUD-like app? Python is plenty fast, especially if you’re relying on c implementations of heavy-lifting stuff.

Any CPU heavy algorithm that does not have a clear boundary to start the C/C++ part is a poor match for Python.

It's a great prototyping language. Sometimes the final product will use a better algorithm because it was found easily in Python then ported to bare metal language.

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