🌐 Mailman 3 February 2019 - Python-list - python.org

how to embed non-tkinter VLC player into grid of tkinter with python?
by Ho Yeung Lee March 16, 2019

March 16, 2019

we have many TV that would like to be monitored, how to embed non-tkinter VLC player into grid of tkinter with python? below code can embeded xterm but not for VLC player import vlc from Tkinter import * import os root = Tk() for r in range(2): for c in range(1): termf = Frame(root, height=100, width=200) termf.pack(fill=BOTH, expand=YES) wid = termf.winfo_id() termf.grid(row=r,column=c) p=vlc.MediaPlayer('file:///home/martin/Downloads/autoweb.mp4') p.get_tk_widget().grid(row=r,column=c) p.play() #os.system('xterm -into %d -geometry 40x20 -sb &' % wid) os.system('vlc --no-fullscreen "file:///home/martin/Downloads/autoweb.mp4" -into %d -geometry 100x200 -sb &' % wid) root.mainloop()

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Re: Implement C's Switch in Python 3
by Sayth Renshaw March 16, 2019

March 16, 2019

> >I am trying to convert a switch statement from C into Python. (why? > >practising). > > > >This is the C code. > > > >printf("Dated this %d", day); > > switch (day) { > > case 1: case 21: case 31: > > printf("st"); break; > > case 2: case 22: > > printf("nd"); break; > > case 3: case 23: > > printf("rd"); break; > > default: printf("th"); break; > > > > } > > printf(" day of "); > > > >#Premise if the use enter an int as the date 21 for example it would print 21st. It appends the correct suffix onto a date. > >Reading and trying to implement a function that uses a dictionary. Not > >sure how to supply list into it to keep it brief and with default case > >of 'th'. > > > >This is my current code. > > > >def f(x): > > return { > > [1, 21, 31]: "st", > > [2, 22]: "nd", > > [3, 23]: "rd", > > }.get(x, "th") > > > > > >print(f(21)) > > > >I have an unhashable type list. Whats the best way to go? > > Skip has commented on lists being unhashable. We can elaborate on that > if you like. > > However, even if you went to tuples (which would let you construct the > dict you lay out above), there is another problem. > > You're looking up "x" in the dict. But the keys of the dict are not > integers, they are lists (or tuples) or integers, so they won't match. > > You _could_ do this: > > return { > 1: "st", 21: "st", 31: "st", > 2: "nd", 22: "nd", > 3: "rd", 23: "rd", > }.get(x, "th") > > which makes distinct entries for each integer value of interest. > > The conventional approach would normally be: > > if x in (1, 21, 31): > return "st" > if x in (2, 22): > return "nd" > if x in (3, 23): > return "rd" > return "th" > > While this works for a small number of choices, if you had a huge dict > with lots of possible values you could return to your > dict-keyed-on-tuples approach. You would need to try each tuple in turn: > > mapping = { > (1, 21, 31): "st", > (2, 22): "nd", > (3, 23): "rd", > } > for key, suffix in mapping.items(): > if x in key: > return suffix > return "th" > > However, for big dictionaries (with many keys) you loose a key strength > of dicts: constant time lookup. You can see the above code (and the > earlier "if" code) are rather linear, with run time going up linearly > with the number of keys. You're better with the int->string single value > dict version. > > Cheers, > Cameron Simpson It seems odd with C having switch that its cleaner and more efficient than python where we are having to implement our own functions to recreate switch everytime. Or perhaps use a 3rd party library like https://github.com/mikeckennedy/python-switch You have both given good options, it seems there are no standard approaches in this case. Cheers Sayth

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Re: ConfigParser: use newline in INI file
by Ned Batchelder March 7, 2019

March 7, 2019

On Saturday, October 1, 2016 at 6:25:16 PM UTC-4, Thorsten Kampe wrote: > * Ben Finney (Sun, 02 Oct 2016 07:12:46 +1100) > > > > Thorsten Kampe <thorsten(a)thorstenkampe.de> writes: > > > > > ConfigParser escapes `\n` in ini values as `\\n`. > > Indenting solves the problem. I'd rather keep it one line per value > but it solves the problem. If you want to have \n mean a newline in your config file, you can do the conversion after you read the value: >>> "a\\nb".decode("string-escape") 'a\nb' --Ned.

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Lifetime of a local reference
by Marko Rauhamaa March 2, 2019

March 2, 2019

Consider this function: def fun(): f = open("lock") flock.flock(f, fcntl.LOCK_EX) do_stuff() sys.exit(0) Question: can a compliant Python implementation close f (and, consequently, release the file lock) before/while do_stuff() is executed? I couldn't find an immediate answer in the documentation. Marko

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Re: Lifetime of a local reference
by Marko Rauhamaa Feb. 28, 2019

Feb. 28, 2019

Roel Schroeven <roel(a)roelschroeven.net>: > In the absence of any other mention of bindings being removed, to me > it seems clear that bindings are not automatically removed. Otherwise > many things become ambiguous. Example: the documentation for dicts > defines "d[key] = value" as "Set d[key] to value". Does that mean it > can get unset later behind your back? Of course not. Nothing is so obvious here. A Python implementation is free to do anything at all that complies with correct semantics. Sometimes correct behavior is unspecified. In your case, "d[key] = value", the binding can disappear if the name d becomes "stale". d[key] will be bound if anybody should look but if the compiler or runtime environment can prove nobody will every look, it might be able to optimize it away. If you accept that open("xyz") can silently close the file immediately, sometime later or never, you should have no problem believing that f = open("xyz") could behave the same way. > It's purely an implementation detail. As long as the visible behavior > of the program complies with the language specification, the compiler > can do as it wishes. And that's the key: what is specified for Python? It would appear nothing has been stated explicitly so it would be dangerous for a Python application to rely on assumed semantics. Marko

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dash/underscore on name of package uploaded on pypi
by ast Feb. 28, 2019

Feb. 28, 2019

Hello I just uploaded a package on pypi, whose name is "arith_lib" The strange thing is that on pypi the package is renamed "arith-lib" The underscore is substitued with a dash If we search for this package: pip search arith arith-lib (2.0.0) - A set of functions for miscellaneous arithmetic (so a dash) For installation both: pip install -U arith_lib pip install -U arith-lib are working well and in both case I got a directory with an underscore C:\Program Files\Python36-32\Lib\site-packages 28/02/2019 16:57 <REP> arith_lib 28/02/2019 16:57 <REP> arith_lib-2.0.0.dist-info What happens ?

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Need help with Python3.4 and Avro
by Mihir Kothari Feb. 28, 2019

Feb. 28, 2019

Hi, I am not sure if this is the right list, but trying to get help from experienced python users for my issue. I have posted the issue in stackoverflow, but yet to see any response. I am trying my luck here. I have my question here: https://stackoverflow.com/q/54833834/3165644 If needed, I can give the details in this email too, please let me know. Regards, Mihir.

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Using PyArg_ParseTuple to with optional fields.
by Anthony Flury Feb. 28, 2019

Feb. 28, 2019

I am trying to write an extension module with a function (actually an __init__ method, but I am not sure that matters) where the function can be called as either : my_func() or my_func( a, b, c, d) - where a,b,c,d are all doubles. I would prefer not to allow the function to be called with some arguments specified - it is either all four - or none. I have tried the following format strings to PyArg_ParseTuple : * "dddd" - but this a mandatory 4 doubles - doesn't allow for the no argument scenario * "|dddd" - allows no arguments - but also allows only one, or just two, or three - i.e. not all or nothing * |(dddd) - allows no argument, but passing 4 arguments expects a 4-tuple - i.e. my_func( (a,b,c,d) ) which is unnecessarily complex Can I do what I want with a single call to PyArg_ParseTuple ? -- Anthony Flury *Email* : anthony.flury(a)btinternet.com <mailto:Anthony.flury@btinternet.com> *Twitter* : @TonyFlury <https://twitter.com/TonyFlury/>

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Re: Lifetime of a local reference
by Marko Rauhamaa Feb. 28, 2019

Feb. 28, 2019

Chris Angelico <rosuav(a)gmail.com>: > What if an exception gets raised at some point before the function has > returned? The exception object will give full access to the function's > locals. It wouldn't hurt for the Python gods to make an explicit ruling on the matter. Marko

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Embedding Python (3.7) on OSX crash on Py_Initialize when run as bundle
by Arnaud Loonstra Feb. 28, 2019

Feb. 28, 2019

Hi, I'm trying to wrap my head around an OSX app which has python embedded. This works fine if I run the build on the same machine as it is build on. However when using Travis to build the app I can only get it to run from the terminal. A double click on the appdir (or using open) results in a crash. trace: 0 libsystem_kernel.dylib 0x00007fffb9d6cd42 __pthread_kill + 10 1 libsystem_pthread.dylib 0x00007fffb9e5a457 pthread_kill + 90 2 libsystem_c.dylib 0x00007fffb9cd24bb __abort + 140 3 libsystem_c.dylib 0x00007fffb9cd242f abort + 144 4 com.your-company-name.www 0x0000000108c6674e fatal_error + 606 5 com.your-company-name.www 0x0000000108c65b3a _Py_FatalInitError + 26 6 com.your-company-name.www 0x0000000108c65bbe Py_Initialize + 126 I can't figure out what is going wrong. I can only guess that's there's something preventing it to access the python files? The build log on travis is here: https://travis-ci.org/hku-ect/NatNet2OSCbridge/jobs/499348594 It's artefact is here: https://pong.hku.nl/~buildbot/nightly/NatNet2OSCbridge_osx_7ceb.zip Python is build with the following flags: ./configure --prefix $HOME/openFrameworks/apps/devApps/$APPNAME/bin/python --disable-shared --with-openssl=$(brew --prefix openssl); Anybody any pointers or advice? Rg, Arnaud

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