Modern APIs with FastAPI and Python Transcripts
Chapter: Modern language foundations
Lecture: Concept: Type hints
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0:00 Now that you saw how useful type annotations can be, or type hits, let's just review the concept of them really quick.
0:06 So here we have a function with no type information. We have some running max. It's set to nothing in the beginning. What's it supposed to be set to?
0:13 I don't know some larger thing, that could be the largest order, that could be the value of the largest order,
0:20 who knows, right? There's no information communicated there. Also, here's a counter function. It takes something. Based on the name being plural,
0:27 I'm guessing I could loop over those things, but I'm not 100% sure. And then there is a total, probably know what to
0:32 do with that, right? So this is not super helpful. Adding types lights up a lot of insight into how it's meant to be used.
0:39 So now we have a optional int. So it starts out as nothing, but it's supposed to be set to an integer. And here we have a counter.
0:46 It takes terrible things so I could loop over it. And what's in them? It's an item. Because it's an item,
0:52 the editors know that it has a value and a name and it says "we return
0:56 an integer". So just reading this code without doing anything else or seeing how it's
0:59 used, we know much more about what's possible as well as our editors know what we should be able to do. So if we try to, add a,
1:07 you know, some kind of field lookup or something that doesn't exist, while we're looping over the items, it will be able to help us and say,
1:12 "No, you're doing that wrong. Its name or value, those are your only two choices". Cool, right?