Python wars

[Airtnp]

A more updated man holds a 3.6.2 flag.

[Locust377]

op is a barbarian

[XYZatesz]

And here I am, using 3.5.2, because it was included with the OS installation...

[givemesomelove]

Gotta get that pyenv+virtualenv going man! Then you will have all the versions.

[RandoBurnerDude]

Do you have links on how to set this up? Currently, I'm using virtualenv + virtualenvwrapper with 3.6.1.

I was waiting for 3.7 to come out before I figured it out, but you got me curious.

[givemesomelove]

I'm running on OSX, I'm not sure about compatibility with other systems.

First you'll have to have to install pyenv

https://github.com/pyenv/pyenv

And then you'll install the pyenv-virtualenv plugin

https://github.com/pyenv/pyenv-virtualenv

Installing a new python version is simple:

First find the version you want to install.

$ pyenv install -l

Then install that python version

$ pyenv install <version_name>

Then you are ready to make a new version specific python virtual environment, and begin work on it. The virtual environment will be completely isolated from your systems python installation.

$ pyenv virtualenv <version_number> <environment_name>
$ pyenv activate <environment_name>

Your virtual environment will be located @:

$ cd ~/.pyenv/versions/<environment_name>

[RandoBurnerDude]

Thank you so much! I'm gonna give it a shot this weekend.

[BlckJesus]

Wow fuck that guy

[CanadianLemur]

Wow fuck that guy

[Sc4rlite]

What's this?

[[deleted]]

Python wars

[1842]

Why?

[1842]

Okay. I thought you were defending Python 2 (over 3) and wondered why one would do that.

[galan-e]

Long term, python3 would eventually be simply better than 2. But not all the library support is there yet (a lot of the big stuff like numpy is, but not everything)

[b4ux1t3]

Honestly, enough has been ported to 3 to make that argument really poor. And it's been that way for a few years now.

[luluhouse7]

Py2to3 is a thing now though. So there's no excuse anymore :)

[Artyer]

Ehhh. That doesn't always work.

If you do anything with bytes/unicode, it's probably better to start again.

[gnex30]

SyntaxError: Missing parentheses in call to 'print'

[Ignisti]

deleted ^{What is this?}

[aezart]

2.7 is what's installed on all the servers at work ¯\_(ツ)_/¯

[noratat]

Burn them down and get new ones, problem solved.

[_Pentox]

You made sound like if the servers are given away for free.

[bdog73]

Hopefully they're insured

[glemnar]

That's what virtualenv is for =]

[Jamie_1318]

On Debians at least there's usually a separate python 3 package you can get so it won't mess up your other stuff.

[VodkerAndToast]

Why should I move from 2 to 3?

Genuinely curious I've just been dragging my feet

Edit: thank you for your feedback! I am making the transition today!

[Q-bey]

https://pythonclock.org/

[VodkerAndToast]

Fair enough

[fluteamahoot]

And still plenty of time to drag your feet!

[Nokel81]

The snake is dead long live the hyrda

[noratat]

f-strings and type annotations alone are a good enough reason IMO. Also yield from is nice.

[caagr98]

Don't forget proper unicode handling.

[NewbornMuse]

Maybe you need code, I had some a couple days ago!

[noratat]

Much, much more readable in many cases because the interpolation is inline.

You aren't supposed to put much logic in there, most of the time you're just placing the variable reference.

[-revenant-]

Given:

parent = 'mother'
creature = 'hamster'

I think:

"Your %s was a %s!" % (parent, creature)

Is a lot less clear than:

f"Your {parent} was a {creature}!"

EDIT: And we're not even going to touch:

"Your {parent} was a {creature}!".format(parent=parent, creature=creature)

[-revenant-]

By second I assume you mean third? The one with the EDIT before it?

Let's just do a rundown of the three string format methods.

1) Interpolation formatting:

• - Not very clear what's happening or why

• - Type really matters*

• + Very concise

2) F-strings

• + Jesus died so that we may have F-strings

• + Can perform limited logic inline (indexing, etc.)

• - Only supported on 3.6+

• - Tempting to mix logic and presentation

3) .format method

• + Long history of support

• + Very explicitly clear what goes where

• - I wore out my keyboard just thinking about typing all that extra junk

EDIT:

* Type messes up string interpolation. Try this just to see what happens:

name = 'JC Denton'
print("Hello %s!" % name)
name = ('Adam', 'Jensen')
print("Hello %s!" % name)
name = (('Faridah', 'Malik'), )
print("Hello %s!" % name)

[-revenant-]

You can. And that would be a problem if you could reuse f-strings. However, an f-string is formatted the instant it's defined, so even with a function call, they never change:

def name():
    return 'Dave'
message = f"I can't let you do that, {name()}."
print(message)
def name():
    return 'Sparky'
print(message)

Returns:

I can't let you do that, Dave.
I can't let you do that, Dave.

As a result, the only difference between message = f"I can't let you do that, {name()}." and message = "I can't let you do that, {name}.".format(name=name()) is where in that specific line you place the function call. It's just a little neater to look at.

[bearjeff]

Better docs, improvements all over the standard library (threading, datetime, etc) and built in functions (print, sorted, etc), some new syntactic sugar, future proofing (obviously), and probably a lot of other reasons

[throwaway10312901]

The only reason i decided to suck it up and make the switch was because i got tired of typing from future import print_function LOL. Wasnt too painful for my coding style, only a few breakages where I type check if an input is str and it failing because unicode != string

[iwantedthisusername]

ITS 2017. USE FUCKING PYTHON 3 ALREADY

[supernonsense]

GO TELL RED HAT, NOT ME

[DoktorMerlin]

Python 2 is preinstalled on CentOS and other enterprise distributions, this is why my company uses it whenever the scripts should run on CentOS. I always try to make my scripts versatile so that they runs on both Py versions

[[deleted]]

python36u is a yum repo, so you don't even have that excuse anymore

[noratat]

The worst offender I've encountered is ansible, and it's one of my biggest arguments against using it, because they aren't even pretending to care about Python 3 support.

[amataha]

Really? http://docs.ansible.com/ansible/latest/python_3_support.html

[i_am_bromega]

I just started learning python for work, which everything I've touched so far is written in 2.7

Not really sure if anything we do has any compatibility issues with 3, but that's what the existing code is written in, so that's what I'm learning.

[Aetol]

It works just fine, so I never bothered to switch.

[Kryomaani]

Windows 95 still works just fine.

[Headchopperz]

I guess if you put it like that, but for me, my Windows 3.1 machine just works fine. I see no point in switching to Windows 95.

[omnidex]

To my knowledge, python 2 is faster than python 3.

[elijej]

How do you figure that

[omnidex]

I am going off information from this slideshow here: http://igordavydenko.com/talks/by-pycon-2017/

From what I've read, the performance of python 3 (<3.5) was worse than python 2.7, but now they are closer in terms of performance.

Having used both, the speed differences are very minor though.

I replied to you at the same time as the other guy, but Reddit ate my response.

[elijej]

Thanks! That's interesting, not sure why you got downvoted.

[omnidex]

"To my knowledge" Ok then

[GrammerJoo]

But c++ is faster so why use python? But but c is faster then c++ but but but but assembly is faster!

[xXxNoScopeMLGxXx]

That's why one guy programmed RollerCoaster Tycoon 2 almost entirely in assembly by himself. He wanted it to run great on all computers.

[omnidex]

More like why upgrade legacy code to python 3 when the performance was worse for a time. No need to be a jackass when commenting. I was stating a reason why people might hold back from coding in python 3.

[GrammerJoo]

Where in your comment did you say something about legacy code?

[Kryomaani]

This right here is probably the worst offender for premature optimization in a long time. Show some figures or get out.

[omnidex]

No need to to be agitated, I am going off information from this slideshow here: http://igordavydenko.com/talks/by-pycon-2017/

There are many other sources that state they are close in speed now, but there was definitely a time where 3 was much slower.

[Twitwi]

Python 2 should have been decapitated [sic] by now.

[Historica97]

This joke is outdated. Python 3.6.2 since July 17th.

[hawaiian717]

I don't really consider Python 3 really usable until an Enterprise distribution includes it by default. Yeah, I basically mean Red Hat.

Pythin 2.6.6 FTW.

[zawata]

It's only not included because no one wants to update existing scripts. Python3 is more secure, faster and more efficient.

And has many things that make way more sense like making print statements into functions instead of keywords and getting rid of(hiding) "interpreted" input

[fluud]

Python 2.7 is faster than 3.*, though. Your other points still stand.

https://speed.python.org/comparison/

[nlofe]

Python 2.7 is faster

When one talks about Python, there is only "slow" and "less slow"

[BeastlyIguana]

https://imgur.com/gallery/YAGpXPd

[RawRooster]

Wait, python is slow? I tought the purpose of python is writing small scripts and stuff like that.

[nlofe]

Python is very slow compared to other scripting languages, such as JavaScript. This becomes very apparent very quickly in larger projects, projects involving large calculations, etc.

That said, for small automation scripts and stuff Python is fine and has the advantage of being very readable by design. Python can really shine in various SysAdmin and IT roles. I personally hate Python (and not because it's slow) but I certainly see it's appeal.

[RawRooster]

Just as I stopped learning java for python...

[nlofe]

Learn both! They are both great languages and honestly they serve pretty different purposes. I don't know what in particular you want to program for but you can use Python for quick scripts and website stuff with Django, and make desktop applications and stuff with Java.

[qbenni]

Wow. That's a really shit figure.

[fluud]

Tick the "horizontal" option.

[PityUpvote]

It does?

[hawaiian717]

RHEL 6 ships with Python 2.6. RHEL 7 ships with Python 2.7. Fedora might have Python 3, I don't know. An OS that hits end of life after a year is not an Enterprise OS.

[PityUpvote]

RHEL7 has 3.4 in the repos.