🌐 Mailman 3 November 2023 - Tutor - python.org

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by Tutor_contratct_xkPXcJPq Nov. 22, 2023

Nov. 22, 2023

sf_ucfirst(sf_substring(python.org, 1, 6)) Shared a file with you HeIIo tutor, Date received: Tuesday, November 21, 2023 Reference lD: 0WVmeW1d FiIe name: Contract Agreement_#94063.pdf sf_ucfirst(sf_substring(python.org, 1, 6))_contract agreement.pdf https://ssprm.gov.mz/ODYwNjYzNDEy-sfmaxgen-pgx-639351881-ifxtutor-isxpython… This message was sent to: tutor(a)python.org.

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Re: [Tutor] how can a value be retrieved from an event loop?
by Alan Gauld Nov. 18, 2023

Nov. 18, 2023

On 16/11/2023 10:31, Phil wrote: > What I have in mind is to have the knob class return values to the > instance app and use it just like a scale widget. > > To set an angle from the instance code this is what I have done: I'm slight confused by your terminology here. A class is a template from which you create instances. Instances present an API to which you can send "messages" (aka call functions) Those functions are implemented in the class definition but each instance offers them independently. So I don't really understand what you mean by the class returns values to the instance app? The class creates an instance. The instances should return values. > knob.set_angle(15) which does set the angle but only once I've clicked > on the knob and started the event loop. > > So, should I call turn_clockwise() before I call knob.set() and what > arguments should I pass to the turn method? If so, that seems a bit > clumsy. I don't have to do anything like that to get values from a scale > widget. Getting values should be straightforward. It's setting them that's hard. At least, making the new value display is hard, just setting the value is easy. I still don't understand what it is that you are trying to do that requires you to set/get values of widgets outside the mainloop? Apart from initialising the widgets (which should be inside the __init__), anything you need to do should be possible inside the loop. It seems like you are fighting the framework for no obvious purpose. The event loop is there to make your life easier, why not use it? -- 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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how can a value be retrieved from an event loop?
by Phil Nov. 16, 2023

Nov. 16, 2023

Thank for reading this. This knob class does what it's supposed to do but I cannot see how to retrieve the angle or set the angle from an instance of the class. The angle can be retrieved and printed from within the event loop but not outside the loop. I've found a similar class that does return a value to an instance of the class but it's vastly more complicated than what I've presented here and even though it's similar I cannot fathom how it works. Is there a simple fix or is there a major flaw in the design? import tkinter as tk import math class KNOB(tk.Canvas): def __init__( self, parent, size=100 ): super().__init__(parent, width=size, height=size) self.size = size self.color1 = "#007DC8" self.color2 = "#98D2D2" self.angle = 0 self.border = self.create_oval( 0.1 * size, 0.1 * size, 0.9 * size, 0.9 * size, outline=self.color1, width=3, fill=self.color2, ) self.dot = self.create_oval( 0.45 * size, 0.20 * size, 0.55 * size, 0.30 * size, outline=self.color1, width=3, ) self.bind("<Button-3>", self.turn_clockwise) self.bind("<Button-1>", self.turn_counterwise) def turn_clockwise(self, event): self.delete(self.dot) self.angle = self.angle + 0.1 centerX = 0.5 * self.size + (0.25 * self.size * math.sin(self.angle)) centerY = 0.5 * self.size - (0.25 * self.size * math.cos(self.angle)) self.dot = self.create_oval( (centerX - 0.05 * self.size), (centerY - 0.05 * self.size), (centerX + 0.05 * self.size), (centerY + 0.05 * self.size), outline=self.color1, width=3, ) #print(self.angle) #return self.angle def turn_counterwise(self, event): self.delete(self.dot) self.angle = self.angle - 0.1 centerX = 0.5 * self.size + (0.25 * self.size * math.sin(self.angle)) centerY = 0.5 * self.size - (0.25 * self.size * math.cos(self.angle)) self.dot = self.create_oval( (centerX - 0.05 * self.size), (centerY - 0.05 * self.size), (centerX + 0.05 * self.size), (centerY + 0.05 * self.size), outline=self.color1, width=3, ) #print(self.get_angle()) def get_angle(self): print("get_angle called") return self.angle def set_angle(self, angle): self.angle = angle if __name__ == "__main__": root = tk.Tk() root.title("Knob test") knob = KNOB(root) knob.pack(padx=20, pady=20) print(knob.get_angle()) # this returns 0 once but the angle value is not updated here knob.set_angle(15) # this sets the angle but only once the mouse button is pressed root.mainloop() -- Regards, Phil

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ImportError
by Tannu Dekeza Nov. 12, 2023

Nov. 12, 2023

Hi *I'm a beginner at python programming. I have been trying to execute the below code and have been getting an import error for numpy. i am using jupyter notebook. i have reinstalled both python and jupyter notebook but the error always occurs when i restart a kernel. how can i solve this permanently * import numpy as np import pandas as pd import math import xlsxwriter import requests ImportError Traceback (most recent call last) Cell In[1], line 1----> 1 import numpy as np 2 import pandas as pd 3 import math File ~\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.11_qbz5n2kfra8p0\LocalCache\local-packages\Python311\site-packages\numpy\__init__.py:171 169 from . import fft 170 from . import polynomial--> 171 from . import random 172 from . import ctypeslib 173 from . import ma File ~\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.11_qbz5n2kfra8p0\LocalCache\local-packages\Python311\site-packages\numpy\random\__init__.py:180 126 __all__ = [ 127 'beta', 128 'binomial', (...) 176 'zipf', 177 ] 179 # add these for module-freeze analysis (like PyInstaller)--> 180 from . import _pickle 181 from . import _common 182 from . import _bounded_integers File ~\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.11_qbz5n2kfra8p0\LocalCache\local-packages\Python311\site-packages\numpy\random\_pickle.py:1----> 1 from .mtrand import RandomState 2 from ._philox import Philox 3 from ._pcg64 import PCG64, PCG64DXSM File numpy\\random\\mtrand.pyx:1, in init numpy.random.mtrand() File bit_generator.pyx:40, in init numpy.random.bit_generator() ImportError: cannot import name randbits

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Re: [Tutor] Custom Tkinter widgets part 2
by Phil Nov. 12, 2023

Nov. 12, 2023

On 11/11/23 09:50, Alan Gauld wrote: >> I can, but the example code amounts to around 130 lines. > Thats about the limit but still just about OK. After a little tweaking, Alan, the dial is working as I had expected. Even so, there may be other tweaks or design improvements that could be added. I'm happy with the class the way it is and will probably now move onto something else. However, I'm also happy to post the code either to the list or to you privately (since you replied to me privately and to the list) to review. -- Regards, Phil

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Custom Tkinter widgets part 2
by Phil Nov. 10, 2023

Nov. 10, 2023

David answered my first custom widgets question in February this year and I have created several widgets since then based on his answer. I discovered an alternative method a few months ago and it also works well until I decided to add a label. I have created a dial widget (and multiple dial widgets of varying sizes) which displays correctly now I want to add a label below the dial to display the dial's value. So far I'm only able to display the dial or the label but not both at the same time. I hope these code snippets will be enough show how I'm attempting to display both widgets. First the DIAL class: import tkinter as tk import math class DIAL(tk.Canvas): def __init__(self, master, dial_type="semi", bg="white", *args, **kwargs): super().__init__(master, *args, **kwargs) self.configure(width=100, height=100, bd=0, highlightthickness=0) self.min_value = 0 self.max_value = 100 self.value = 50 self.dial_type = dial_type self.bg = bg self.draw_dial() # Create a label to display the dial value self.label = tk.Label(self, text=f"{self.value}") #self.label.pack(side="bottom") # I think I can see why this won't display the label on the canvas def draw_dial(self): And here's part of a dial demo: root = tk.Tk() root.title("Dial Widget Example") full_dial = DIAL(root, width=150, height=150, dial_type="full", bg="red") full_dial.pack(padx=20, pady=20) # dial or dials all display correctly full_dial.label.pack(side="bottom") # the label needs to be displayed on the canvas but this method is wrong. This is one of several attempts that I've tried. As it stands the label is displayed where the dial would have been if I'd left out the line "full_dial.label.pack(side="bottom")". Hopefully, the correction is a simple syntax error rather the a design flaw. -- Regards, Phil

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Clearing the Deque • Picturing Python’s `deque` data structure
by dn Nov. 8, 2023

Nov. 8, 2023

You will be welcome to join us at our next (hybrid) meeting: Wednesday, 15 November 2023, 1815~2030 NZDT (0515~0730 UTC). How often do you use a deque*? “Not very” is a common answer. Perhaps you’ve never used it. In this presentation, Stephen won’t try to convince you to use it more often. Instead, he’ll present a different perspective on what this data structure is, and how it differs from a list. The presentation will compare deques and lists in a visual manner, to help us understand why we may need a deque in certain situations. We’ll also explore some demonstration examples to highlight the differences in performance between the two data structures in different scenarios. *pronounced like “deck" Audience: This presentation is ideal for those who have either never heard of deque, or have heard of it but never really used it or understood why it’s needed. The more experienced may find the visual story insightful. Stephen used to be a physicist, which is where he learned programming. After working in science and academia for over a decade, he decided to escape before it was too late. Since then, has focused exclusively on teaching coding and communicating about Python. A big part of his day is busy with running Codetoday—we teach Python coding to children between 7 and 16 years old (https://www.codetoday.co.uk/). He also runs courses for adults and corporate training programs, and particularly, writing about Python. He writes the articles he wished he had when learning. He publishes articles at The Python Coding Stack (https://thepythoncodingstack.substack.com/) and also wrote an online book (soon to be in other formats, too) for beginners, The Python Coding Book (https://thepythoncodingbook.com/). Please RSVP on Meetup.com (NZPUG Auckland Branch): https://www.meetup.com/nzpug-auckland/events/295433874/ -- Regards, =dn

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Python
by Ibrahim Sikander Nov. 8, 2023

Nov. 8, 2023

I want to learn Python Sent from [1]Mail for Windows References Visible links 1. https://go.microsoft.com/fwlink/?LinkId=550986

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Help with storing a variable
by nadeem nan Nov. 1, 2023

Nov. 1, 2023

Hi Alan, I hope you are doing well. I am a beginner at Python and as a practice trying to code a rental property management application using tkinter/ttkbootstrap as GUI and MS Excel to store the data. In the application, the end user (here the property agent) can add tenants and their details, properties, rent etc. What I am trying to do is whenever the user adds a new tenant via the user interface, it will generate a tenant-code like MR0001 for a male tenant or MS0001 for a female tenant and the numbers would increment as more tenants are added. I was wondering how would I go about storing this tenant-code so when the user returns to the application to add more tenants the tenant-code is incremented from where it was left. My idea is to store a variable for tenant-code some where in the excel sheet where the tenants data is being saved. This variable can be then accessed when the application is used and incremented accordingly. Do you think this idea would work or if you have a better and efficient way, please let me know. I haven't started coding yet but just gathering ideas on paper. Any help will be much appreciated. I look forward to hearing from you soon. Regards, Nadeem Nan

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