Simon Willison’s Weblog

Entries tagged python, programming

Filters: Type: entry × python × programming ×

For a Django application, deployed on Heroku, what are my options for storing user-uploaded media files?

S3 is really a no-brainer for this, it’s extremely inexpensive, very easy to integrate with and unbelievably reliable. It’s so cheap that it will be practically free for testing purposes (expect to spend pennies a month on it).

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Which companies in London are using Python?

We use Python/Django for—we’re based in London.

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What advice would Simon Willison give to a beginner Python/Django developer?

Build something and put it on the internet. Make sure you have an easy way to deploy new versions (Heroku is a good bet if you don’t want to figure out Fabric). Pick a project that’s useful to you—a simple blogging engine is often a good bet, or maybe something that aggregates together your posts from Twitter and Instagram and so on. Or come up with something a bit more creative!

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Which should I learn: Python or PHP?

Python will teach you more about programming than PHP—and you’ll be able to learn PHP easily if you learn Python first.

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What are some hidden features of Python?

Generators and Iterators are pretty amazing. These two tutorials will really open your eyes as to how powerful they can be:

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How can some really large services (like Dropbox) afford to use Python as a primary language, if it’s one to two orders of magnitude slower than other, compiled languages?

Because raw language speed often doesn’t matter that much. In the case if Dropbox the client software spends most of its time waiting for bits to load from the network or from disk. Most large websites spend their time waiting for the database. You can’t speed up network or disk performance by using a faster language.

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Is it bad practice to have a variable that has the same name as a function?

Yes, it’s definitely not a good idea. In Python functions and variables share the same namespace, so if you create a variable with the same name as a function you won’t be able to call that function.

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What are the best resources for learning regular expressions?

The O’Reilly book on Regular Expressions is absolutely superb. It will help you build a much deeper understanding if how they actually work than any online tutorial I’ve seen.

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What is a good video series on learning Python?

It probably won’t teach you the basics, but we’ve collected 190 videos from conference talks about Python here:

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Why does Python load imported modules separately for different files, unlike C or PHP? Isn’t that inefficient in terms of memory usage?

It doesn’t—you’re misunderstanding how Python’s module system works. If two different places have “import os” in them, the os module is only imported and executed once—it’s cached in the sys.modules dictionary so you can see it happen if you want to. The key thing to understand is that “import os” attaches the os module to the “os” symbol within the current file’s scope, loading it only if it hasn’t been loaded already.

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