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0 pointsaftbit4y ago0 comments

random.shuffle() has bitten me that way a few times too:

    array = random.shuffle(array)

because I expected it to return a copy or reference, instead making my array None.

It would also enable chaining operations:

    array = array.append(A).append(B).sort()

In-place vs immutable copy is a language design choice with tradeoffs on both sides, but there's no reason that I can see to not return a reference to the list.

Perhaps recognizing this is really the job of an external linter. Sometimes I wonder if the future of enforcing canonical formatting on save like "gofmt" or "black" will extend to auto-correcting certain goofy errors on each save.

mypy would yell at you about this, but afaik type-checked python still isn't the norm.

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2 comments · 1 top-level

int_19h4y ago· 1 in thread

In Python, a function that makes and returns a copy would be idiomatically named shuffled(). Consider sorting:

   xs.sort()        # in-place
   ys = sorted(xs)  # copy

As for functions returning the object - I think it's a hack around the absence of direct support for such repetition in the language itself. E.g. in Object Pascal, you'd write:

   with array do
   begin
      append(A);
      append(B);
      sort;
   end;

Or better yet, in Smalltalk:

   array append(A); append(B); sort.

https://en.wikipedia.org/wiki/Method_cascading

igouy4y ago

Also

https://dart.dev/guides/language/language-tour#cascade-notat...

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