Building a full-text search engine in 150 lines of Python code (2021)

Re:Building a full-text search engine in 150 lines of Python... by evnp on Friday January 24, 2025 @07:00AM (#42812297)

Is this any different from `filter(bool, tokens)`? (similar to the JS equivalent mentioned in a sibling)

If not, I'm now curious why the `None` special case was added to `filter`..

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Re:Building a full-text search engine in 150 lines of Python... by hacked_greenhat on Friday January 24, 2025 @10:36AM (#42814107)

https://stackoverflow.com/questions/8748036/is-there-a-built...

While this doesn't explain why filter accepts None as the lambda, I think the fact that there are no builtin identity function kind of explains why. It's easier to write None rather than put an identity lambda. I reckon it also makes it easier for a compiler to optimize this specific case.

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Re:Building a full-text search engine in 150 lines of Python... by evnp on Sunday January 26, 2025 @10:34AM (#42830709)

Thanks for the explanation. I take your point, but in the `filter` case `bool` seems just as easy as `None`, but with the added benefit that no awareness of a special case is needed -- any python programmer should understand how the `bool` builtin works. Curious if there's any downside.

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