What's Coming in Python 3.8

Post by [deleted] » Wed, Jul 17, 2019, 11:24 PM UTC

heydenberk wrote: post #172

kbd wrote: post #118

Despite controversy, walrus operator is going to be like f-strings. Before: "Why do we need another way to..." After: "Hey this is great". People are wtf-ing a bit about the positional-only parameters, but I view that as just a consistency change. It's a way to write in pure Python something that was previously only possible to say using the C api.

I'd used f-string-like syntaxes in other languages before they came to Python. It was immediately obvious to me what the benefit would be. I've used assignment expressions in other languages too! Python's version doesn't suffer from the JavaScript problem whereby equality and assignment are just a typo apart in, eg., the condition of your while loop. Nonetheless, I find that it ranges from marginally beneficial to ma…

Post by brilee » Wed, Jul 17, 2019, 11:25 PM UTC

philsnow wrote: post #40

I noticed some changes to pickle; do people still use pickle for Real Work? Potential vulnerabilities aside, I got bitten by some migration issue back in the 2.2 to 2.4 transition where some built-in types changed how they did their __setstate__ and __getstate__ (iirc) and that caused objects picked under 2.4 to not unpickle correctly under 2.2 or something like that. After that I never wanted to use pickle in produc…

Post by orangecat » Wed, Jul 17, 2019, 11:27 PM UTC

BuckRogers wrote: post #182

The problem with modern Python is that it's trying to recreate C# or Java. Which leaves it with nothing, because it'll only end up an inferior version of the languages/platforms of which it's attempting to duplicate. When I was into Python, I liked it because it was a tighter, more to the basics language. Not having 4 ways to format strings and so forth. I don't think Python can defeat Java by becoming Java. It'll lo…

  # 1: loop condition obscures what you're actually testing
  while True:
      data = read_data()
      if not data:
          break
      process(data)

  # 2: 7 lines and a stray variable
  done = False
  while not done:
      data = read_data()
      if data:
          process(data)
      else:
          done = True

  # 3: duplicated read_data call
  data = read_data()
  while data:
      process(data)
      data = read_data()

  while (data := read_data()):
      process(data)

Post by airstrike » Wed, Jul 17, 2019, 11:28 PM UTC

fny wrote: post #224

heydenberk wrote: post #172

Earlier quoted context omitted.

I'd used f-string-like syntaxes in other languages before they came to Python. It was immediately obvious to me what the benefit would be. I've used assignment expressions in other languages too! Python's version doesn't suffer from the JavaScript problem whereby equality and assignment are just a typo apart in, eg., the condition of your while loop. Nonetheless, I find that it ranges from marginally beneficial to ma…

I love string interpolation! But this seems to take it to a bizarre level place just to save a few keystrokes. Seriously, how is f"{now=!s}" substantially better than f"now={str(now)}"? Ergonomically, I see little benefit for the added complexity.

Post by stefco_ » Wed, Jul 17, 2019, 11:30 PM UTC

Asooka wrote: post #209

stefco_ wrote: post #146

There's a lot of talk in this thread about Python going down-hill and becoming less obvious/simple. I rather like modern python, but I agree that some features (like async/await, whose implementation fractures functions and libraries into two colors [0]) seem like downgrades in "Pythonicity". That said, I think some things have unquestionably gotten more "Pythonic" with time, and the := operator is one of those. In c…

You are supposed to write for x in iter(f.readline, ""): Or if you don't know what readline will return you can wrap it in your own lambda: for x in iter(lambda:f.readline() or None, None): There is a lot you can do with iter to write the kind of loops you want but it's not well known for some reason. It's a very basic part of the language people seem to overlook. Walrus does however let you write the slightly more u…