🌐 Mailman 3 December 2017 - Python-list - python.org

merits of Lisp vs Python
by Mark Tarver Jan. 12, 2018

Jan. 12, 2018

How do you compare Python to Lisp? What specific advantages do you think that one has over the other? Note I'm not a Python person and I have no axes to grind here. This is just a question for my general education. Mark

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Regarding the error: TypeError: can’t pickle _thread.lock objects
by Winston Manuel Vijay Jan. 5, 2018

Jan. 5, 2018

Hi, It would be of immense help, if someone could provide a suitable solution or related information that helps to sort out the below stated issue- Ø I had installed the Python version 3.6.4 Ø Then I installed the package: Tensorflow Ø Installed g2p.exe by downloading from GitHub Ø Then tried running the below command- g2p-seq2seq --interactive --model <model_folder_path> (model_folder_path: is the path to an English model 2-layer LSTM with 512 hidden units CMU Sphinx dictionary downloaded from the CMU Sphinx website) Following the above procedure, I encountered the following error: TypeError: can’t pickle _thread.lock objects-please find the attached screenshot for your reference. Thanks, A.Winston Manuel Vijay ________________________________ This e-mail and any files transmitted with it are for the sole use of the intended recipient(s) and may contain confidential and privileged information. This email is sent for the intended recipient(s) only. If by an addressing or transmission error, this mail has been misdirected to you, you are requested to delete this mail immediately. If you are not the intended recipient(s), please reply to the sender and destroy all copies of the original message. Any unauthorized review, use, disclosure, dissemination, forwarding, printing or copying of this email, and/or any action taken in reliance on the contents of this e-mail is strictly prohibited and may be unlawful. Where permitted by applicable law, this e-mail and other e-mail communications sent to and from GSR e-mail addresses may be monitored.

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Problems with imports on multiple threads, with embedded Python
by geoff.bache＠gmail.com Jan. 5, 2018

Jan. 5, 2018

Hi all, I have a multithreaded application using an embedded Python 3.6.4 (upgraded from 3.6.2 today in the hope that the problem was now solved: it doesn't seem to be). The standard library is in a zip file. So long as only one thread is running Python at a time it seems to work fine. But there seems to be a problem with the module importing when several Python threads are active. I get a variety of errors indeterministically, usually indicating that some symbol hasn't been imported. This occurs both in my own code and in the standard library. The most frequent is probably this line: dt = datetime.strptime(dtStr, fromFmt) which produces AttributeError: module '_strptime' has no attribute '_strptime_datetime' at random. Does anyone have any insight into this problem? Regards, Geoff Bache

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How to create a python extension module from a shared library?
by Etienne Robillard Jan. 3, 2018

Jan. 3, 2018

Hi all, I would like to extend uWSGI by creating a CPython extension module for the libuwsgi.so shared library included in the distribution. My goal is to use this automatically generated CPython module for extending uWSGI. I have summarized my current approach here: https://mail.python.org/pipermail/tutor/2017-December/112475.html So far, I have tried to use CFFI and pycparser to generate the Python bindings, however CFFI and pycparser doesn't handle C directives like #include and #define. I also attempted using clang to preprocess the "uwsgi.h" header found in the uWSGI distro with pycparser.parse_file() to generate a AST, however the generated AST object seems incorrect. Is there any way to reflect a shared library into a CPython module? I know that using "nm -D libuwsgi.so" I can get a list of available functions for this module. However, I have very little experience with ctypes and CFFI. Do I need to modify CFFI to allow it to parse a C header with libclang? I'm guessing CFFI/clang or ctypes should allow me to reflect the shared library, but I'm not sure about which method is the most appropriate. What do you think? Sincerely, Etienne -- Etienne Robillard tkadm30(a)yandex.com https://www.isotopesoftware.ca/

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Re: Goto (Posting On Python-List Prohibited)
by bartc Jan. 1, 2018

Jan. 1, 2018

On 29/12/2017 21:55, Lawrence D’Oliveiro wrote: > On Saturday, December 30, 2017 at 9:03:50 AM UTC+13, bartc wrote: >> Why most newer, higher level languages don't, I don't know. Perhaps >> because the people who design them want to make programming harder? > > I don’t use gotos in C code. Why should it be “harder” in a higher-level language? > Good for you. Looking at 14 million lines of Linux kernel sources, which are in C, over 100,000 of them use 'goto'. About one every 120 lines. My own low level sources use about one goto every 400 lines. It's hardly a lot. If one is used, it's because it was handy to use it, until such time as it can be replaced with proper logic. But such logic will usually be more convoluted. BTW, looking at 220,000 lines of CPython sources, in C (an old distribution I had to hand), there are 2600 gotos, about one every 85 lines. And those are the ones are directly visible as gotos, and not hidden behind macros. I understand that on Linux, the CPython dispatcher makes use of label pointers, using 'goto *opcode_targets[*next_instr++]' to do a faster byte-code dispatch than using switch. You I guess would have written it without that, and we'd all have to suffer 10% slower speed (or whatever) for your principles. That's assuming you could have got rid of the other 2600 gotos as well. -- bartc

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Copy-on-write friendly Python garbage collection
by breamoreboy＠gmail.com Jan. 1, 2018

Jan. 1, 2018

An interesting write up on something that is incorporated into Python 3.7 https://engineering.instagram.com/copy-on-write-friendly-python-garbage-col… -- Kindest regards. Mark Lawrence.

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Re: Anaconda Navigator : Add App
by Wu Xi Jan. 1, 2018

Jan. 1, 2018

that is a very slow manager. too slow.

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tkinter MP working like a charm
by Wu Xi Jan. 1, 2018

Jan. 1, 2018

from tkinter import * # I cant see anything wrong with this , it works like a charm from tkinter import messagebox # is there a serious concern doing things his way ? import asyncio , threading , random # goal is multi tasking with the GUI not freezing before loop completed # which is being achieved here ! def _asyncio_thread(async_loop): async_loop.run_until_complete(do_urls()) def do_work(async_loop): """ Button-Event-Handler starting stuff """ threading.Thread(target=_asyncio_thread, args=(async_loop,)).start() async def one_url(url): """ One task. """ sec = random.randint(1, 8) await asyncio.sleep(sec ) return 'url: {} --- sec: {}'.format(url, sec) async def do_urls(): """ Creating and starting 10 tasks. """ tasks = [one_url(url) for url in range(10)] completed, pending = await asyncio.wait(tasks) results = [task.result() for task in completed] print('\n'.join(results)) def do_nofreeze(): messagebox.showinfo(message='see, Tkinter is still responsive') def submain(async_loop): root = Tk() b1 = Button(master=root, text='do work', command= lambda:do_work( async_loop)).pack() b2 = Button(master=root, text='Frozen?', command=do_nofreeze ).pack() root.mainloop() if __name__ == '__main__': async_loop = asyncio.get_event_loop() # all in this loop submain(async_loop)

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Re: Goto (Posting On Python-List Prohibited)
by bartc Jan. 1, 2018

Jan. 1, 2018

On 31/12/2017 12:41, Chris Angelico wrote: > On Sun, Dec 31, 2017 at 11:33 PM, bartc <bc(a)freeuk.com> wrote: >> On 30/12/2017 23:54, Chris Angelico wrote: >>> I've written code that uses dirty tricks like that to avoid >>> duplication. It's at least as much of a problem as actual duplication >>> is. Generally, the 'goto' solution results in subsequent programmers >>> (such as my future selves) staring at the code for 30-60 seconds to >>> figure out what it's doing. I don't like to do that to myself, much >>> less to people I actually admire and respect. >> >> >> The problem is having to stare at the code for even longer to figure out the >> even dirtier tricks you had to use to avoid gotos. >> > > Dirtier tricks like... named functions? I like to write clean and readable code. If I thought introducing functions, whether local or not, as a way of avoiding goto was worth doing, I would do so. So in this case I disagree with dragging in named functions and introducing an extra level of control flow just to avoid duplicating half a dozen lines of code. I would just duplicate those lines (with a comment that they have to match the other set so that they are maintained in sync). For other uses of goto, I've introduced (not in Python or C but my own stuff) features to avoid the need some of those uses. For example, extra loop controls, and loop controls that work with nested loops. I've also experimented with a feature intended purely to get to common clean-up code, but that had little advantage over using goto other than not writing 'goto', and thus avoiding some of the stigma (but you will also know it will do a one-off forward jump to a common point). (Actually, none of my code ever needs to use 'goto' anyway, as I can also write it as 'go to'. That's effective if anyone does a 'grep' on my code looking for 'goto' instances...) -- bartc

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Mr. Conway in 50 lines of code
by Wu Xi Dec. 31, 2017

Dec. 31, 2017

import time , itertools __doc__=" Mr Conway_s Game Of Life simulation in python 2 and 3 " width = 55 ; height = 55 # size of life habitat , e.g. a simulated meteorite, bolide , etc. vmap = [['D' for w in range(width)] for h in range(height)] # D = Dead at first def neighbours(point): x,y = point yield x + 1 , y yield x - 1 , y yield x , y + 1 yield x , y - 1 # this is proof that life can emerge inside of computers and cellular automatons, yield x + 1 , y + 1 # and evolve through memory, attack other cells and morph into toads, pulsars, etc.. yield x + 1 , y - 1 yield x - 1 , y + 1 # spray your memory with space alien patterns and life evolution will start in your machine ! yield x - 1 , y - 1 def ageing(habitat): newstate = set() recalc = habitat | set(itertools.chain(*map(neighbours, habitat))) for point in recalc: count = sum((neigh in habitat) for neigh in neighbours( point)) if count == 3 or (count == 2 and point in habitat): # standard rule def. - a life cell having less than 2 alive neighbours will die newstate.add(point) return newstate glider = set([ (40,40) , (41,40) , (42,40) , (40,41) , (41,42) ]) # patterns of life: gliders, boats, guns, imps, toads, pulsars and so on previous = set([ ( 0, 0) , ( 1, 0) , ( 2, 0) , ( 0, 1) , ( 1, 2) ]) # offset on screen / place during last step in life for lifetime in range(300): # number of simulated lifetime steps (e.g. 300 / 0.1 sleep = 30 seconds) before death occurs try: time.sleep( 0.1 ) # slow it down previous = glider ; glider = ageing(glider) for tup in glider : el=tup ; xx=el[0] % width ; yy =el[1] % height ; vmap[xx][yy]='L' # Live cell has emerged for tup in previous : el=tup ; xx=el[0] % width ; yy =el[1] % height if tup not in glider : vmap[xx][yy]='D' # Dead cell # put more life patterns in this lifespan loop and let them evolutionize! vtxt = [''.join('*' if cell=='L' else ' ' for cell in row) for row in vmap] print('\033[H\033[J') # clear screen print('\n'.join(reversed(vtxt))) except: pass print("Simulated lifetime of the glider is over. May there live soon a new glider in the life habitat of your screen.")

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