New features you can't use unless you are in Python 3

Post by tripzilch » Thu, Jun 15, 2017, 2:42 PM UTC

chestervonwinch wrote: post #32

Fej wrote: post #20

Does anyone use 2.x by choice? I've only seen it required as to not break legacy code.

Yes. My reason is that I simply don't really care that much. It's the default on all my systems, so why bother putting in the effort to use something that doesn't appear to offer much advantage to me personally? I use python for my personal research, so my particularly situation affords me this laziness. edit: I don't mean this as a knock on py3. All I'm saying is that my situation and uses for python allow me to be…

Post by collinmanderson » Thu, Jun 15, 2017, 3:02 PM UTC

lwf wrote: post #223

Animats wrote: post #220

Earlier quoted context omitted.

You're not. von Rossum has to maintain Python 2.7 as part of his day job. Things I still have in Python 2.7: - Code that runs on low-end shared hosting. There's a Python 3, but it's 3.2, the least-compatible version. No "six", and "u'xyz' isn't allowed. - ROS, the Robot Operating System. Python 3 support is coming, but it's not really here yet. I converted over the dedicated servers and some IoT stuff a year ago. The…

> You're not. von Rossum has to maintain Python 2.7 as part of his day job. *van Rossum I wouldn't say that's an accurate statement of what Guido does every day :) (nb: I work at Dropbox, and have worked with Guido at Dropbox.)

Post by collinmanderson » Thu, Jun 15, 2017, 3:07 PM UTC

Animats wrote: post #222

iak8god wrote: post #85

Earlier quoted context omitted.

I'm in similar situation wrt what I use python for, and suffered from the same apathy until quite recently. Man, it was really easy to switch, and completely worth it just for the little things (like UTF-8 as default encoding for strings). It's really painless, but if you want to ease into it, I recommend using __future__ in your py2 stuff for now just to get you into a py3 state of mind: https://docs.python.org/2/li…

UTF-8 isn't CPython's default encoding for strings. The internal encodings are ASCII, UTF-16, or UTF-32, depending on the widest character in the string. I would have made UTF-8 the internal representation, and generated an array of subscript indices only when someone random-accessed a string. If the string is being processed sequentially, as with for c in s : ... you don't need an index array. You don't need them fo…

Post by tripzilch » Thu, Jun 15, 2017, 3:20 PM UTC

minitech wrote: post #177

seanwilson wrote: post #172

Earlier quoted context omitted.

How hard would it have been to allow Python 2 and 3 code files to be mixed?

That’s a giant can of worms. One example problem: Python 2 has a type of class (old-style) that doesn’t exist in Python 3. What happens when you try to pass this type of class or one of its instances between the languages? There’s a bunch of stuff like that. You’d end up with a very weighed-down interpreter with a bunch of caveats if you ended up with one at all.

Post by jwilk » Thu, Jun 15, 2017, 3:41 PM UTC

lwf wrote: post #223

Animats wrote: post #220

Earlier quoted context omitted.

You're not. von Rossum has to maintain Python 2.7 as part of his day job. Things I still have in Python 2.7: - Code that runs on low-end shared hosting. There's a Python 3, but it's 3.2, the least-compatible version. No "six", and "u'xyz' isn't allowed. - ROS, the Robot Operating System. Python 3 support is coming, but it's not really here yet. I converted over the dedicated servers and some IoT stuff a year ago. The…

> You're not. von Rossum has to maintain Python 2.7 as part of his day job. *van Rossum I wouldn't say that's an accurate statement of what Guido does every day :) (nb: I work at Dropbox, and have worked with Guido at Dropbox.)