[Python-Dev] Tricky way of of creating a generator via a comprehension expression (original) (raw)

Antoine Pitrou solipsis at pitrou.net
Thu Nov 23 07:30:02 EST 2017


On Thu, 23 Nov 2017 14:17:32 +0200 Serhiy Storchaka <storchaka at gmail.com> wrote:

I used the "yield" statement, but I never used the "yield" expressions. And I can't found examples. Could you please present a real-world use case for the "yield" (not "yield from") expression?

Of course I can. "yield" expressions are important for writing Python 2-compatible asynchronous code while avoiding callback hell:

See e.g. http://www.tornadoweb.org/en/stable/gen.html or https://jdb.github.io/concurrent/smartpython.html

There are tons of real-world code written using this scheme (as opposed to almost no real-world code, even Python 2-only, using "yield" in comprehensions or generation expressions).

Regards

Antoine.



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