🌐 Mailman 3 April 2017 - Tutor - python.org

Scripting Calligra sheets with Python
by Jim Byrnes Jan. 31, 2022

Jan. 31, 2022

I am trying to script Calligra Sheets (formerly KSpread) with python. I have gotten some of the included example scripts to run so I know python scripting is running. I found the following snippet on their website: import KSpread sheet = KSpread.view().sheet() # swap text of B5 and C6 t1 = sheet.text("B5") t2 = sheet.text(6,3) sheet.setText("B5", t2) sheet.setText(6, 3, t1) # swap value of D7 and E8 v1 = sheet.value("D7") v2 = sheet.value(8,5) sheet.setValue("D7", v2) sheet.setValue(8, 5, v1) Error: 'str' object has no attribute 'text' File "file:///usr/share/kde4/apps/sheets/scripts/extensions/myswap.py", line 4, in <module> This error message appeared in a dialog box. I've taught myself some Python but I don't understand what is happening here. Shouldn't t1 be a sheet object? What would cause it to be a str instead? Thanks, Jim

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Desktop Notifications on Linux
by Dharmit Shah June 29, 2017

June 29, 2017

Hi all, I am trying to create a script that will go through the /var/log/secure file on a Linux system and provide desktop notifications for failed login attempts. Here is the code - http://pastebin.com/MXP8Yd91 And here's notification.py - http://pastebin.com/BhsSTP6H I am facing issue in the function "new_attempts_from_last". I am not able to raise a desktop notification from this function. It always fails with this traceback - http://pastebin.com/cgHMScv3 I see this error only when I try to raise a notification from the aforementioned function. If I run test examples under /usr/share/doc/notify-python/examples, it works just fine. Also, if I try to raise a notification from under if __name__ == "__main__":, it works without any issues. So I don't think there's any issue with OS's notification daemon. Running from python shell like below also works fine: In [1]: import notification In [2]: notification.notification("Hey") What am I missing or doing wrong here? If it matters, I am running Fedora 20, python 2.7 and Cinnamon desktop environment. For readability purposes, I have provided pastebin links. Let me know if this is not the correct way. Regards, Dharmit.

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Using venv
by Jim May 30, 2017

May 30, 2017

It has been suggested to me that I should use a virtual environment and venv would be a good choice. I've read through PEP405 and this link [1]. Though some of it seems a little confusing to me, I'm sure I can get it up and running. This question seems a little dumb and maybe I am being a little dense, but then what? Your program/script is done how do you run it? Do you always have to activate your venv and run it from there? I like to run Tkinter programs from a launcher. Would that be possible and what would the command look like? Lately I have been writing some Libreoffice calc macros and evaluating pyspread for it's macro capability. Would modules installed in my venv be available to the spreadsheet programs? Thanks, Jim [1] https://realpython.com/blog/python/python-virtual-environments-a-primer/

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Another set question
by Phil May 1, 2017

May 1, 2017

I'm trying to implement a conditional branch based on a variable type. For example, if c is a character and s is a set with only one member. c = "9" s ={9} if type(c) == a string: do this else: do that An alternative that I've attempted is to test if a set contains one member based on len(). However, I then cannot tell if len() is referring to a single character or a single set with one member. So I'm back to square one. A for loop is indexing mixed lists of characters (one character per list) and lists that a set with one member. I'm only interested in the sets and want to ignore the character lists. I have come up with a method that will probably work but it's become quite messy with multiple compare statements. Something simple and less prone to cause headaches would be better. -- Regards, Phil

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Python 3.6 Extract Floating Point Data from a Text File
by Stephen P. Molnar April 30, 2017

April 30, 2017

I am using the Spyder v-3.1.2 IDE and porting a FORTRAN program that I wrote about 20 years ago to Python Unfortunately, I am very much a novice in Python . I would have managed to extract input data from another calculation (not a Python program) into the following text file. LOEWDIN ATOMIC CHARGES ---------------------- 0 C : -0.780631 1 H : 0.114577 2 Br: 0.309802 3 Cl: 0.357316 4 F : -0.001065 What I need to do is extract the floating point numbers into a Python file What I need to do is extract the floating point numbers into a Python file. Googling the problem has not resulted on any insight as to the solution, and any help will be much appreciated. Thanks in advance. -- Stephen P. Molnar, Ph.D. Life is a fuzzy set www.molecular-modeling.net Stochastic and multivariate (614)312-7528 (c) Skype: smolnar1

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Fwd: Re: Python 3.6 Extract Floating Point Data from a Text File
by Alan Gauld April 30, 2017

April 30, 2017

How, embarrassing, I forgot to CC the list! :-) On 30/04/17 11:09, Stephen P. Molnar wrote: > I would have managed to extract input data from another calculation (not > a Python program) into the following text file. > > LOEWDIN ATOMIC CHARGES > ---------------------- > 0 C : -0.780631 > 1 H : 0.114577 > > What I need to do is extract the floating point numbers into a Python file >From previous posts we know you can extract a line of text so really you are asking how to extract a floating point number from a string. >>> s = ' 0 C : -0.780631' >>> fps = s.split()[-1] # get the last item from the split string >>> val = float(fps) >>> print( val ) Or in one line: val = float( line.split()[-1] ) Obviously if the number were not at the end you would have to use the appropriate index instead of -1... -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.amazon.com/author/alan_gauld Follow my photo-blog on Flickr at: http://www.flickr.com/photos/alangauldphotos

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Tkinter layout question
by Phil April 30, 2017

April 30, 2017

I'm looking for ideas here. A working solution for my sudoku solver is a 9 x 9 grid of entry boxes but it looks a bit basic. So I created a 9 x 9 grid on a canvas which looks much better. I can display digits in the centre of the squares but entering the digits from the keyboard seems to be beyond me. I experimented with entering a digit at the mouse location but it all seems to be too complicated. Perhaps someone can offer a repetitively simple solution? A second experiment involved the earlier grid of entry boxes but with a space between every third row and column. This seems to be more achievable, eventually. Something along these lines: for i in range(9): if i % 4 == 0: place a blank text label else: place an entry box So, how might I enter digits into a grid on a canvas or how could I create a space between a grid entry boxes? -- Regards, Phil

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How to display radiobutton window with no buttons selected?
by boB Stepp April 30, 2017

April 30, 2017

Win7-64bit, Python 3.6.1 When I run the following code, the radiobutton window initially displays with *all* buttons apparently selected. However, when the "Status" button is clicked on, the status is as expected, an empty string for the checked_radiobutton StringVar(). ================================================================================ #!/usr/bin/env python3 import tkinter as tk root = tk.Tk() # Report option selected: def status(): print('You selected the radiobutton: %s' % checked_radiobutton.get()) print() languages = ('Perl', 'JavaScript', 'PHP', 'Python 2', 'Python 3') # Create new variable object to keep track of checked radiobutton: checked_radiobutton = tk.StringVar() for language in languages: # Create new radiobutton: tk.Radiobutton(root, text=language, variable=checked_radiobutton, value=language).pack(anchor='w') checked_radiobutton.set('') tk.Button(root, text='Status', command=status).pack(fill='x') root.mainloop() ================================================================================ I wish the displayed window to initially display with no button selected. What am I missing here? Thanks! -- boB

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Thread Object integration with GPIO
by Marc Eymard April 30, 2017

April 30, 2017

Hello there, I have hooked up an ultrasonic sensor to my Raspberry Pi-enabled robot in order to get continuous distance-to-obstacle reading. The sensor is properly connected via GPIO and already reads the distance properly when running a simple script. However, I need to integrate the sensor reading logic to an existing script provided by PiBorg called YetiBorg.py The way I have decided to go about implementing the sensor reading is by creating a Thread object and update the distance attribute of this very same object from the run() function. The idea is to encapsulate the distance reading within the sensor object as much as possible by i. creating a sensor/thread object and by ii. avoiding global variables. Attached the script I have come up with, which keeps returning multiple run time errors whenever I try to fix it. I believe there are multiple issues, but at least it gives an idea of what I currently want to achieve and how. Can a charitable soul advise whether my approach makes sense and whether I am using the right type of object for the task at hands? I am looking for guidance and willing try completely different approach/objects if necessary. Thanks in advance for sending me into the right direction. Marc

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Thread Object integration with GPIO
by Marc Eymard April 30, 2017

April 30, 2017

Hello there, I have hooked up an ultrasonic sensor to my Raspberry Pi-enabled robot in order to get continuous distance-to-obstacle reading. The sensor is properly connected via GPIO and already reads the distance properly when running a simple script. However, I need to integrate the sensor reading logic to an existing script provided by PiBorg called YetiBorg.py The way I have decided to go about implementing the sensor reading is by creating a Thread object and update the distance attribute of this very same object from the run() function. The idea is to encapsulate the distance reading within the sensor object as much as possible by i. creating a sensor/thread object and by ii. avoiding global variables. Below the script I have come up along with the error print. I believe there are multiple issues, but at least it gives an idea of what I currently want to achieve and how. Can a charitable soul advise whether my approach makes sense and whether I am using the right type of object for the task at hands? I am looking for guidance and willing try completely different approach/objects if necessary. Thanks in advance for sending me into the right direction. Marc ----Python Shell---- 2.7.9 ----OS----- Raspian Pixel on Raspberry Pi Zero ---traceback---- Traceback (most recent call last): File "/home/pi/Desktop/distance sensor class object.py", line 57, in <module> SensorA = Sensor(interval=1, gpio_trig=23, gpio_echo=24) File"/home/pi/Desktop/distance sensor class object.py", line 23, in __init__self.start() RuntimeError: thread.__init__() not called ------sensor.py----- import threading import RPi.GPIO as GPIO import time #GPIO Mode (BOARD / BCM) GPIO.setmode(GPIO.BCM) class Sensor(threading.Thread): """ultrasonic sensor continous distance reading at given interval in seconds""" def __init__(self,interval, gpio_trig, gpio_echo): self.inter = interval self.trig = gpio_trig self.echo = gpio_echo #set GPIO pins direction (IN / OUT) GPIO.setup(gpio_trig, GPIO.OUT) GPIO.setup(gpio_echo, GPIO.IN) self.dist = 0 self.terminated = False self.start() def run(self): while not self.terminated: # set Trigger to HIGH GPIO.output(gpio_trig, True) # set Trigger to LOW after 0.01ms time.sleep(0.00001) GPIO.output(gpio_trig, False) StartTime = time.time() StopTime = time.time() # save StartTime while GPIO.input(gpio_echo) == 0: StartTime = time.time() # save time of arrival while GPIO.input(gpio_echo) == 1: StopTime = time.time() # time difference between start and arrival TimeElapsed = StopTime - StartTime # multiply by sonic speed (34300 cm/s) # and divide by 2, because there and back self.dist = (TimeElapsed * 34300) / 2 time.sleep(self.inter) def get_dist(self): return self.dist #Sensor object "instanciated" with GPIO programmable pins 23 and 24 SensorA = Sensor(interval=1, gpio_trig=23, gpio_echo=24) try: while True: print("Measured Distance = %.1f cm" % SensorA.get_dist()) except KeyboardInterrupt: GPIO.cleanup() SensorA.terminated = True

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