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Comment by matthewmacleod | Hacker News Reader

Some interesting and useful syntax here! However...

I’m also partial to this trick for grabbing just the first element of an array.

  family, = socket.peeraddr

This is the sort of code that really turns me off when I'm digging through Ruby. It adds no clarity and actually looks like a typo. What's wrong with this?

  family = socket.peeraddr.first

It's much clearer what's going on.

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It could be more readable if you use a placeholder variable

  family, _ = socket.peeraddr

Which is more clear to me, but maybe not as much as just using .first

(context: I'm the author)

I do agree with you, but through some failing of my own I still quite enjoy that trick. I included it to highlight the syntax, but I'll add a note saying it's maybe not the best idea to actually use it.

I often use it when I'm running through code in a console.

I put it in production code once, but removed it when I realised the "# This comma is important" comment was longer than just using `.first`

The

    first,_ = list

syntax also works when you're reading the two first items:

    first,second,_ = list

As does `first, second = list.first(2)`.

Right. I think it works better in Python — although I'm partial towards `[family] = socket.peeraddr` or adding parens as the comma is a bit hard to see — because it also asserts that the RHS is a single-item iterable (or however many items you have on the left-hand side:

    >>> [a] = range(1)
    >>> [a] = range(2)
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
    ValueError: too many values to unpack

and it works on any iterable (any object with #to_a in ruby).

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