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

Python Interview Questions
by Krypto Jan. 10, 2019

Jan. 10, 2019

Hi, I have used Python for a couple of projects last year and I found it extremely useful. I could write two middle size projects in 2-3 months (part time). Right now I am a bit rusty and trying to catch up again with Python. I am now appearing for Job Interviews these days and I am wondering if anybody of you appeared for a Python Interview. Can you please share the questions you were asked. That will be great help to me. Thanks,

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How to use multiple instances of the same COM object at the same time
by Jan Dec. 18, 2018

Dec. 18, 2018

Dear Usenet readers, Our company wants to implement about 40 biometric access control devices which have a proprietary DLL with a COM object in it. I've done some research about COM objects and how to use them. Now, I need to connect to every device separately and register for real time events. So, I need about 40 instances of the COM object simultaneously connected and registered to catch all events of all devices. I assumed I needed threading for this, and I have done a simple implementation. All I want to ask is: Does anybody see something that I could have done in a better way? I'm new to COM objects in Python! The program runs fine, it is very basic and I tested it with 3 devices connected at the same time. In production this will be 40! Thanks in advance Jan Source code: # Based on eventappartmentthreading from the win32com demo import sys, os, time import win32com.client import win32api import win32event # sys.coinit_flags not set, so pythoncom initializes apartment-threaded. import pythoncom from threading import Thread threadlist = dict() # this stores the device ids # using the threadid as the key field class ZkEvents: def __init__(self): self.event = win32event.CreateEvent(None, 0, 0, None) thread = win32api.GetCurrentThreadId() print "thread %s " % thread self.dev_id = threadlist[thread] print "Thread Connected For ID %s " % self.dev_id def OnFinger(self): print self.dev_id, print "OnFinger" def OnVerify(self, iUserID=pythoncom.Empty): print self.dev_id, print "OnVerify: %s" % iUserID def OnKeyPress(self, iKey=pythoncom.Empty): print self.dev_id, print "KeyPress: %s" % iKey def WaitWhileProcessingMessages(event, timeout = 60): start = time.clock() while True: # Wake 4 times a second - we can't just specify the # full timeout here, as then it would reset for every # message we process. rc = win32event.MsgWaitForMultipleObjects( (event,), 0, 250, win32event.QS_ALLEVENTS) if rc == win32event.WAIT_OBJECT_0: # event signalled - stop now! return True if (time.clock() - start) > timeout: # Timeout expired. return False # must be a message. pythoncom.PumpWaitingMessages() def TestZkEvents(ip, dev_id): thread = win32api.GetCurrentThreadId() print 'TestZkEvents created ZK object on thread %d'%thread threadlist[thread] = dev_id pythoncom.CoInitialize() zk = win32com.client.DispatchWithEvents("zkemkeeper.ZKEM", ZkEvents) if zk.Connect_Net(ip, 4370): print "Connect %s OK" % ip else: print "Connect %s Failed" % ip try: if zk.RegEvent(1, 65535): # 65535 = register for all events print "RegEvent %s, %s OK" % (ip, dev_id) else: print "RegEvent %s, %s Failed" % (ip, dev_id) except pythoncom.com_error, details: print "Warning - could not open the test HTML file", details # Wait for the event to be signaled while pumping messages. while True: if not WaitWhileProcessingMessages(zk.event): print "No Events From %s During Last Minute" % dev_id zk = None if __name__=='__main__': # this should be a for loop with database fields... t1 = Thread(target=TestZkEvents, args=('192.168.1.211',40)) t1.start() t2 = Thread(target=TestZkEvents, args=('192.168.1.212',45)) t2.start() t3 = Thread(target=TestZkEvents, args=('192.168.1.213',49)) t3.start()

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ipython does not work with latest version of prompt-toolkit
by Cecil Westerhof Dec. 18, 2018

Dec. 18, 2018

When executing: pip3 list --no-cache-dir --outdated I got: prompt-toolkit 1.0.15 2.0.1 wheel PyGObject 3.28.2 3.28.3 sdist youtube-dl 2018.5.30 2018.6.2 wheel So I executed: pip3 install --upgrade prompt-toolkit PyGObject youtube-dl This gave: Successfully installed PyGObject-3.28.3 prompt-toolkit-2.0.1 youtube-dl-2018.6.2 ipython 6.4.0 has requirement prompt-toolkit<2.0.0,>=1.0.15, but you'll have prompt-toolkit 2.0.1 which is incompatible. And when I now execute ipython3, I get: Traceback (most recent call last): File "/usr/local/bin/ipython3", line 7, in <module> from IPython import start_ipython File "/usr/local/lib/python3.5/dist-packages/IPython/__init__.py", line 55, in <module> from .terminal.embed import embed File "/usr/local/lib/python3.5/dist-packages/IPython/terminal/embed.py", line 16, in <module> from IPython.terminal.interactiveshell import TerminalInteractiveShell File "/usr/local/lib/python3.5/dist-packages/IPython/terminal/interactiveshell.py", line 22, in <module> from prompt_toolkit.shortcuts import create_prompt_application, create_eventloop, create_prompt_layout, create_output ImportError: cannot import name 'create_prompt_application' When I now execute: pip3 list --no-cache-dir --outdated I do not get output. So pip3 thinks everything is OK. How do I fix this? Or is the expected that ipython3 will be updated shortly? -- Cecil Westerhof Senior Software Engineer LinkedIn: http://www.linkedin.com/in/cecilwesterhof

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python CAD libraries?
by Jayden Dec. 13, 2018

Dec. 13, 2018

Are there any python CAD libraries that can (1) build simple 3D primitives solids such as spheres, cylinders and so on (2) perform bool operations on 3D solids (3) better if it has some transformations such has scaling, sweeping, and lofting Please recommend some good ones for me? Thanks a lot!!

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py2exe, program has stoped working!?
by skanemupp＠yahoo.se Nov. 23, 2018

Nov. 23, 2018

so i used py2exe and i have the build and the dist-folders. in the distfolder there is a Calculator.exe file. when i run it it just says "Calculator.exe has stopped working" in a popup but the program itself never shows up. wtf!? and when im distributing my program i have to include both catalogues right?

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Are dicts supposed to raise comparison errors
by Robin Becker Aug. 2, 2018

Aug. 2, 2018

A bitbucket user complains that python 3.6.6 with -Wall -b prints warnings for some reportlab code; the example boils down to the following ########## C:\code\hg-repos\reportlab\tmp>cat tb.py if __name__=='__main__': d={'a':1} d[b'a'] = d['a'] ########## C:\code\hg-repos\reportlab\tmp>\python36\python -Wall -b tb.py tb.py:3: BytesWarning: Comparison between bytes and string d[b'a'] = d['a'] I had always assumed that dicts didn't care about the type of keys although some types might cause issue with hashability, but obviously the implementation seems to be comparing b'a' with 'a' (I suppose because they hash to the same chain). Is this code erroneous or is the warning spurious or wrong? -- Robin Becker

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How to start gnuradio
by bengt.tornq＠gmail.com Aug. 1, 2018

Aug. 1, 2018

My gnuradio program does not start in my Mint 17.3 installation. When I invoke the command "gnuradio-companion" I get the following message: ----------------------------- Cannot import gnuradio. Is the python path environment variable set correctly? All OS: PYTHONPATH Is the library path environment variable set correctly? Linux: LD_LIBRARY_PATH Windows: PATH MacOSX: DYLD_LIBRARY_PATH ----------------------------- My exported paths, in the .bashrc file, are: export PYTHONPATH=$PYTHONPATH:/usr/lib/python2.7/dist-packages export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/bin Grateful for hints on how to find out the reason and to solve the problem.

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unittest.TestCase.assertRaisesRegex throws DeprecationWarning
by Uri Even-Chen July 31, 2018

July 31, 2018

Hi, We are using unittest.TestCase.assertRaisesRegex in our Django project (Speedy Net / Speedy Match - https://github.com/urievenchen/speedy-net), and I always prefer calling Python function parameters by name. So we call self.assertRaisesRegex with parameters (keyword arguments) expected_exception, expected_regex and callable - as documented on https://docs.python.org/3/library/unittest.html#unittest.TestCase.assertRai… . You can see our code on https://github.com/urievenchen/speedy-net/blob/master/speedy/core/accounts/… . When I run tests regularly (with "./manage.py test") they pass, But when I run tests with "python -W error::DeprecationWarning manage.py test", (with Python 3.5.5), I receive errors like this: DeprecationWarning: 'callable' is an invalid keyword argument for this function See the full errors here: https://travis-ci.org/urievenchen/speedy-net/jobs/410482655 (by the way, with Python 3.4.6 the tests pass). Do you know what is the problem and why I receive these deprecation warnings? Thanks, Uri. *Uri Even-Chen* [image: photo] Phone: +972-54-3995700 Email: uri(a)speedy.net Website: http://www.speedysoftware.com/uri/en/ <http://www.facebook.com/urievenchen> <http://plus.google.com/+urievenchen> <http://www.linkedin.com/in/urievenchen> <http://github.com/urievenchen> <http://twitter.com/urievenchen>

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ANN: Wing Python IDE version 6.1 released
by Wingware July 31, 2018

July 31, 2018

Hi, Wingware has just released Wing 6.1 <http://wingware.com/news/2018-07-30>, which adds PEP 8 reformatting, includes a How-To for Windows Subsystem for Linux, supports the Qt5Agg backend for matplotlib, allows configuring a path for code snippets, supports evaluating generator expressions that use data from the enclosing scope in the Debug Probe, improves auto-completion for pygame, and makes about 45 other minor improvements.For details, see https://wingware.com/pub/wingide/6.1.0/CHANGELOG.txt Download Now <https://wingware.com/downloads> About Wing Wing is a family of cross-platform <http://wingware.com/doc/install/supported-platforms> Python IDEs with powerful integrated editing, debugging, unit testing, and project management features. Wing runs on Windows, Linux, and OS X, and can be used to develop any kind of Python code for web, desktop, embedded scripting, and other applications. Wing 101 <https://wingware.com/downloads/wing-101> and Wing Personal <https://wingware.com/downloads/wing-personal> omit some features and are free to download and use without a license. Wing Pro <https://wingware.com/downloads/wing-pro> requires purchasing <https://wingware.com/store/purchase> or upgrading <https://wingware.com/store/upgrade> a license, or obtaining a 30-day trial at startup. Version 6 introduces many new features, including improved multi-selection, much easier remote development <https://wingware.com/doc/proj/remote-hosts>, debugging from the Python Shell, recursive debugging, PEP 484 and 526 type hinting, PEP 8 reformatting, support for Python 3.6 and 3.7, Vagrant <https://wingware.com/doc/howtos/vagrant>, Jupyter <https://wingware.com/doc/howtos/jupyter>, Django <https://wingware.com/doc/howtos/django> 1.10+ and 2.0, and Windows Subsystem for Linux, improved mainloop support for matplotlib, easier Raspberry Pi <https://wingware.com/doc/howtos/raspberry> development, optimized debugger, OS X full screen mode, One Dark color palette, Russian localization (thanks to Alexandr Dragukin), expanded free product line, and much more. For details, see What's New in Wing Version 6 <https://wingware.com/wingide/whatsnew>. Wing 6 works with Python versions 2.5 through 2.7 and 3.2 through 3.7, including also Anaconda, ActivePython, EPD, Stackless, and others derived from the CPython implementation. For more product information, please visit wingware.com <https://wingware.com/> Upgrading You can try Wing 6 without removing older versions. Wing 6 will read and convert your old preferences, settings, and projects. Projects should be saved to a new name since previous versions of Wing cannot read Wing 6 projects. See also Migrating from Older Versions <https://wingware.com/doc/install/migrating> and Upgrading <https://wingware.com/doc/install/upgrading>. Links Release notice: https://wingware.com/news/2018-07-30 Downloads and Free Trial: https://wingware.com/downloads Buy: https://wingware.com/store/purchase Upgrade: https://wingware.com/store/upgrade Questions? Don't hesitate to email us at support(a)wingware.com. Thanks, -- Stephan Deibel Wingware | Python IDE The Intelligent Development Environment for Python Programmers wingware.com

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Python Console Menu
by Tcpip July 31, 2018

July 31, 2018

Hi all, Im new with python, im working on a Python console Menu, I found some examples on Git, but what I need to understand is how I can call a subprocess. Here is an Example , if choice==1: print "Test SSH Connection (check ssh to all hosts)" ## You can add your code or functions here #print_menu() elif choice==2: print "Menu 2 has been selected" ## You can add your code or functions here elif choice==3: print "Menu 3 has been selected" ## You can add your code or functions here elif choice==4: print "Menu 4 has been selected" ## You can add your code or functions here elif choice==5: print "Menu 5 has been selected" ## You can add your code or function here Thanks.

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