[Python-Dev] PEP 572: Assignment Expressions (original) (raw)

Steve Holden steve at holdenweb.com
Mon Apr 23 11:59:35 EDT 2018

On Mon, Apr 23, 2018 at 8:28 AM, Antoine Pitrou <solipsis at pitrou.net> wrote:

On Mon, 23 Apr 2018 00:44:44 -0500 Tim Peters <tim.peters at gmail.com> wrote: ​[...]

> if (diff := x - xbase) and (g := gcd(diff, n)) > 1: > return g > That's so Pythonic I could cry ;-) ​[...] The second part, especially, where you use the result of an assignment expression as a comparison operand, looks definitely un-Pythonic. ​Which, I suppose, underlines that Pythonicity is in the mind of the beholder.​

The assignment expression seems like a vary natural way to introduce variables of limited (controlled?) scope, and the class-namespace special case doesn't seem horrible enough to put me, at least, off the idea. There will, of course, be those who abuse assignment expressions, and I'm very much looking forward to seeing what David Beazley makes of them.

While Tim's expression might look (superficially) like C, the five-line alternative isn't exactly an inspiring example of Pythonicity, is it?

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