🌐 Mailman 3 May 2018 - Python-list - python.org

Re: www.python.org down
by Chris Angelico May 7, 2018

May 7, 2018

On Sun, May 6, 2018 at 9:22 PM, Gilmeh Serda <gilmeh.serdah(a)nothing.here.invalid> wrote: > On Mon, 30 Apr 2018 10:38:54 -0700, Jorge Gimeno wrote: > >> Not sure who to report to, but the site comes back with a 503. Anyone >> know where I can direct this to? > > Why would you report it? Give it at least a day before you're going > berserk with "reports"! If there's a serious problem, they will see to it > that a replacement site is launched that will give info on what happened. > Sit back and stay calm! > > Trust me, there is nothing more annoying than having to wade through a > crapload of "error reports" early in the morning. And especially from > those morons who end their reports with "What's wrong?" Gee, are you > coming over to fix things? > > I wish I had a penny for every such "report" we receive to our external > support box, I'd be rich today. > So you'd rather the site just stay down until the right person happens to notice it? Nice to know that your attitude towards your web site's users is that they are "morons", and even more indicative that you consider that people should let the site be down for a minimum of 86,400 seconds before it's considered serious enough to actually report. ChrisA

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Re: Weird side effect of default parameter
by Robert Latest May 7, 2018

May 7, 2018

Steven D'Aprano wrote: > Python function default values use *early binding*: the default parameter > is evaluated, ONCE, when the function is defined, and that value is used > each time it is needed. Thanks, "early binding" was the clue I was missing. robert

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EuroPython 2018: Call for Proposals (CFP) is open
by M.-A. Lemburg May 7, 2018

May 7, 2018

We’re looking for proposals on every aspect of Python: programming from novice to advanced levels, applications and frameworks, or how you have been involved in introducing Python into your organization. EuroPython is a community conference and we are eager to hear about your experience. * https://ep2018.europython.eu/en/call-for-proposals/ * Please also forward this Call for Proposals to anyone that you feel may be interested. Important Notice: New Conference Layout --------------------------------------- Please note that the conference layout has changed compared to previous years, the main conference (talks) is now only three days: * Monday and Tuesday: trainings, workshops and Beginners’ Day only * Wednesday, Thursday, Friday: talks, panels, posters, helpdesks, open sessions, etc. (no trainings!) Submit your proposal -------------------- * https://ep2018.europython.eu/en/call-for-proposals/ * Submissions will be open until Sunday, May 20. Given the compact timing this year, one should not bet on an extension, please submit your proposals as early as possible - also to reduce work load of the reviewers. Thank you. Presenting at EuroPython ------------------------ We will accept a broad range of presentations, from reports on academic and commercial projects to tutorials and case studies. As long as the presentation is interesting and potentially useful to the Python community, it will be considered for inclusion in the program. Can you show something new and useful? Can you show the attendees how to: use a module? Explore a Python language feature? Package an application? If so, please consider submitting a talk. Submission types ---------------- * Regular Talk / approx. 110 slots * Trainings / 12 slots. * Panels * Interactive * Posters / 15 slots * Helpdesk / 6 slots Tracks ------ You may suggest your submission for a track. Tracks are groups of talks, covering the same domain (e.g. Django), all in the same room in a row. You may choose one of these specialized domains / tracks: * Business Track (running a business, being a freelancer) * DevOps * Django Track * Educational Track * General Python * Hardware/IoT Track * PyData Track * Science Track * Web Track PyData EuroPython 2018 ---------------------- As usual, there will be a PyData track at this year’s conference. The PyData track is run in cooperation with NumFocus and the PyData Edinburgh meetup. Discounts for Content Contributors ---------------------------------- Since EuroPython is a not-for-profit community conference, it is not possible to pay out rewards for talks or trainings. For talks, posters, help desk and organizing a panels or interactive sessions we will give out a 25% discount coupon valid for one conference ticket. Trainers will receive a 100% discount coupon for both a conference ticket and a training pass to compensate for the longer preparation time. More details ------------ Since there's a lot more detail to how the CFP works, please check the CFP page for additional information: * https://ep2018.europython.eu/en/call-for-proposals/ * Enjoy, -- EuroPython 2018 Team https://ep2018.europython.eu/ https://www.europython-society.org/ PS: Please forward or retweet to help us reach all interested parties: https://twitter.com/europython/status/993418719756996608 Thanks.

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ImportError: cannot import name _remove_dead_weakref
by joseph pareti May 7, 2018

May 7, 2018

on an Ubuntu VM with : 1. Linux JP-Paid-UBUNTU-DSVM 4.13.0-1014-azure 2. Python 3.5.4 :: Anaconda custom (64-bit) $ manta manta_genSimData.py Loading script 'manta_genSimData.py' Traceback (most recent call last): skipping some details ... File "/anaconda/lib/python2.7/weakref.py", line 14, in <module> from _weakref import ( *ImportError: cannot import name _remove_dead_weakref* Script finished.

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Re: write to file
by Sharan Basappa May 6, 2018

May 6, 2018

On Sunday, 6 May 2018 10:48:12 UTC+5:30, Chris Angelico wrote: > On Sun, May 6, 2018 at 3:10 PM, Sharan Basappa <sharan.basappa(a)gmail.com> wrote: > > On Saturday, 5 May 2018 21:47:33 UTC+5:30, Steven D'Aprano wrote: > >> On Sat, 05 May 2018 08:45:39 -0700, Sharan Basappa wrote: > >> > >> > Thanks a lot. I have actually tried print with file handle as a > >> > parameter (the last option). I see that the file is created but nothing > >> > is logged. > >> > >> That could be a file buffer issue. Nothing will actually be written to > >> the disk until either the buffer is full, or you close the file. Try > >> calling fh.flush() from time to time, or use: > >> > >> print(msg, file=fh, flush=True) > >> > >> > >> although things may be different on Windows. (For example, you may not be > >> able to open the file while it is still open in Python.) > >> > >> > >> > >> -- > >> Steve > > > > Steve, > > > > I agree that flushing could be an issue but I assume when the program closes, buffered data should be flushed even if I am explicitly flushing. This I did not see happening. Probably, I have to spend some additional time. > > -- > > Can you post a complete (but preferably small) example of a program > that creates a file but doesn't properly write to it? > > ChrisA Thanks, Everyone. I was probably making some mistake. I re-checked again and added file handle to the prints. Everything works fine. Below is the code ... # Imports from matplotlib import pyplot as plt from sklearn.datasets import load_iris import numpy as np import pickle fh = open("ML_PY_2.log","w+") # load the data with load_iris from sklearn data = load_iris() features = data['data'] feature_names = data['feature_names'] target = data['target'] target_names = data['target_names'] labels = target_names[target] plength = features[:,2] # use numpy operations to get setosa features is_setosa = (labels == 'setosa') # this the important step max_setosa = plength[is_setosa].max() min_non_setosa = plength[~is_setosa].min() print("data\n",data,file=fh) print("target\n",target, file=fh) print("target_names\n",target_names,file=fh) print("labels\n",labels,file=fh) print("is_setosa\n",is_setosa,file=fh) print("plength\n",plength,file=fh) print('maximum of setosa: {0}.'.format(max_setosa)) print('minimum of others: {0}.'.format(min_non_setosa)) fh.close()

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Re: write to file
by Sharan Basappa May 6, 2018

May 6, 2018

On Saturday, 5 May 2018 21:47:33 UTC+5:30, Steven D'Aprano wrote: > On Sat, 05 May 2018 08:45:39 -0700, Sharan Basappa wrote: > > > Thanks a lot. I have actually tried print with file handle as a > > parameter (the last option). I see that the file is created but nothing > > is logged. > > That could be a file buffer issue. Nothing will actually be written to > the disk until either the buffer is full, or you close the file. Try > calling fh.flush() from time to time, or use: > > print(msg, file=fh, flush=True) > > > although things may be different on Windows. (For example, you may not be > able to open the file while it is still open in Python.) > > > > -- > Steve Steve, I agree that flushing could be an issue but I assume when the program closes, buffered data should be flushed even if I am explicitly flushing. This I did not see happening. Probably, I have to spend some additional time.

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Re: write to file
by Sharan Basappa May 6, 2018

May 6, 2018

On Saturday, 5 May 2018 22:05:53 UTC+5:30, Mark Lawrence wrote: > On 05/05/18 12:25, Sharan Basappa wrote: > > In my program, I have print statements for debugging. > > However, these are cluttering the display. So, I am trying to save > > these to a file but somehow I cant seem to get it correct. > > Use the logging module https://docs.python.org/3/library/logging.html > for debugging, it's far easier in the longer term. > > > > > For example, the following are the print statement in my program: > > print("target_names\n",target_names) > > > > To print to a file, I have opened the file using - fh = open("ML_PY_2.log","w+") > > Beyond this, I see that fh.write has to be used but most of the examples I see only show how strings are saved. > > > > Can I get input how to covert the above print statement to save into the file? > > You'll need to do some string formatting. Take your pick from :- > > The old but still heavilly used C style > https://docs.python.org/3/library/stdtypes.html#old-string-formatting > > The new style > https://docs.python.org/3/library/string.html#format-string-syntax > > If you have Python 3.6 f-strings > > > > > Thanks in advance > > > > -- > My fellow Pythonistas, ask not what our language can do for you, ask > what you can do for our language. > > Mark Lawrence Mark, Thanks a lot. I will take a look at logging module. I have used logger module in perl which really takes out a lot of coding effort

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Why is calling eval so slow?
by Steven D'Aprano May 6, 2018

May 6, 2018

I understand that calling eval() on a string is going to be slow, since the string has to be parsed, compiled, and then executed. But why is it so slow when called on function __code__ objects and pre- compiled byte-code? Here are the tests I ran: # calling a regular function python3.5 -m timeit -s "f = lambda: 99" "f()" # evaluating a function code object python3.5 -m timeit -s "f = (lambda: 99).__code__" "eval(f)" # estimate the overhead of the eval name lookup python3.5 -m timeit "eval" # evaluating a pre-compiled byte-code object python3.5 -m timeit -s "f = compile('99', '', 'eval')" "eval(f)" # evaluating a string python3.5 -m timeit "eval('99')" And the results on my computer: # call a regular function 1000000 loops, best of 3: 0.245 usec per loop # evaluate the function __code__ object 1000000 loops, best of 3: 1.16 usec per loop # overhead of looking up "eval" 10000000 loops, best of 3: 0.11 usec per loop which means it takes four times longer to execute the code object alone, compared to calling the function object which executes the code object. Why so slow? # evaluate the pre-compiled byte-code 1000000 loops, best of 3: 1.13 usec per loop # parse, compile and evaluate a string 10000 loops, best of 3: 23.5 usec per loop That one, at least, makes perfect sense to me :-) -- Steve

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Meaning of abbreviated terms
by T Berger May 5, 2018

May 5, 2018

What does the "p" in "plist" stand for? Is there a python glossary that spells out the meanings of abbreviated terms?

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Re: ipython install
by Sharan Basappa May 5, 2018

May 5, 2018

On Saturday, 5 May 2018 15:02:33 UTC+5:30, Steven D'Aprano wrote: > On Sat, 05 May 2018 00:20:26 -0700, Sharan Basappa wrote: > > > After this, when I type ipython on command prompt, I don't get anything > > on my windows. > > You don't get *anything*? Not even an error? > > > > -- > Steve like typical behaviour when you don't have the application installed on your computer, it actually open up a browser and gives results for ipython using bing

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