Pattern Matching in Python

37 points by amosson 5 years ago · 4 comments

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ggm 5 years ago

Always wanted a switch coding style. Now, offered one i am having second thoughts introspecting if my code improves for readability if I use one. I think on balance yes. I've always like this approach to a single value or expression gating choices.

Also wondering about the degenerate forms of fall through alternates, so it's a stack of code optionally run.

There is another link to c code switches and duffs device in hn recently

pmart123 5 years ago
Switch statements can work well from a readability standpoint such as the HTTP error example they use. However, I almost feel it is more Pythonic to use a dictionary instead, collapsing the function into:
def http_error(status):
```
  try:
    return HTTP_STATUS_CODES[status]
  except KeyError:
    return "Something else"
```
Also, method polymorphism always seemed more powerful and intuitive to me than switch statements when the operation is something like:
```
  multiply(scalar, scalar)
  multiply(vector, scalar)
  multiply(matrix, scalar)
```

singhrac 5 years ago

Wow I love this. This is one of my favorite features of Rust/OCaml (along with variant types / data-bearing-enums).

I think the latter would help a lot with error handling in particular, not to mention defining protocols.

pansa2 5 years ago

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Pattern Matching in Python

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