🌐 Mailman 3 March 2024 - Tutor - python.org

Can you help me with this memoization simple example?
by marc nicole March 30, 2024

March 30, 2024

I am creating a memoization example with a function that adds up / averages the elements of an array and compares it with the cached ones to retrieve them in case they are already stored. In addition, I want to store only if the result of the function differs considerably (passes a threshold e.g. 500000 below). I created an example using a decorator to do so, the results using the decorator is slightly faster than without the memoization which is OK, but is the logic of the decorator correct ? anybody can tell me ? My code is attached below: import time def memoize(f): cache = {} def g(*args): if args[1] == "avg": sum_key_arr = sum(list(args[0])) / len(list(args[0])) elif args[1] == "sum": sum_key_arr = sum(list(args[0])) if sum_key_arr not in cache: for ( key, value, ) in ( cache.items() ): # key in dict cannot be an array so I use the sum of the array as the key if ( abs(sum_key_arr - key) <= 500000 ): # threshold is great here so that all values are approximated! # print('approximated') return cache[key] else: # print('not approximated') cache[sum_key_arr] = f(args[0], args[1]) return cache[sum_key_arr] return g @memoize def aggregate(dict_list_arr, operation): if operation == "avg": return sum(list(dict_list_arr)) / len(list(dict_list_arr)) if operation == "sum": return sum(list(dict_list_arr)) return None t = time.time() for i in range(200, 15000): res = aggregate(list(range(i)), "avg") elapsed = time.time() - t print(res) print(elapsed)

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Re: [Tutor] Thanks for your review
by Alan Gauld March 26, 2024

March 26, 2024

Always reply-All when respoding to the list. Otherwise it only goes to the individual and you lose the benefit of the "hive mind" on the list. (I've CCd the list on this reply) On 26/03/2024 16:42, Jonathan Wilson wrote: > main(sys.argv[1], sys.argv[2]) > > * File "C:\Users\918856164\Desktop\SFSU\UpdateDBFromConsole.py", line > 61, in main* > > * newDBFileName = date.today().strftime("%y.%-m.%-d") + ' ' + > dbFileName* > > *ValueError: Invalid format string* That's correct, the format string is not a valid strftime format. I'm not certain what format you want but I suspect it might be: newDBFileName = date.today().strftime("%y.%m.%d") + ' ' + dbFileName Which would output something like: 2024.03.26 SomeFilename.db > newDBFileName = today.strftime("%m%d ") > > Here is some actual code: >>>> d = dt.datetime(2020,6,18) >>>> d.strftime("{} {} ").format(d.day, d.month) > '18 6 ' >>>> d.strftime("%d %m ") > '18 06 ' -- 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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Thanks for your review
by Jonathan Wilson March 26, 2024

March 26, 2024

Hello. I am getting an error in the beginning of my python script and it is referring to this line: newDBFileName = today.strftime(.format(today.month, today.day)) + ' ' ^ SyntaxError: invalid syntax Can someone tell me what the invalid syntax is here for this line? Appreciate any help you can give. (new python coder) The arrow is pointing to the .ahead of the format. Best, Jonathan

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Expanding a frame into an expanding window
by Phil March 25, 2024

March 25, 2024

Thank you for reading this. I've created a custom widget that I'm importing into an app. The app includes 3 frame classes including the imported custom widget class. The widgets on those frames all use the grid method. When the app window is expanded the frames expand and frame's widgets move except for the frame that uses the imported class. That frame expands but the widgets on that frame remain in place. So there must be a problem with the custom widget class. The following are 2 simplified versions of the custom widget class to illustrate the problem. The version that uses the pack method does expand correctly but, of course, the two widgets are under each other rather than beside each other. The frame that uses the imported class also expands but the two widgets do not move. import tkinter as tk class SimpleEntry(tk.Frame): def __init__(self, parent, bg_colour="light blue"): # default colour is light blue super().__init__(parent, bg=bg_colour) self.enter_label = tk.Label(self, text="enter a number") self.number_enter = tk.Entry(self) self.enter_label.grid(row=0, column=0, padx=5, pady=5, sticky="nsew") self.number_enter.grid(row=0, column=1, padx=5, pady=5, sticky="nsew") ''' import tkinter as tk class SimpleEntry(tk.Frame): def __init__(self, parent, bg_colour="light blue"): super().__init__(parent, bg=bg_colour) self.enter_label = tk.Label(self, text="enter a number") self.number_enter = tk.Entry(self) self.enter_label.pack(expand=True) self.number_enter.pack(expand=True) ''' I've spent all day on this and all I've achieved is a headache. -- Regards, Phil

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Thank you for your review and assistance
by Jonathan Wilson March 25, 2024

March 25, 2024

Hello. I am getting an error in the beginning of my python script and it is referring to this line: newDBFileName = today.strftime(.format(today.month, today.day)) + ' ' ^ SyntaxError: invalid syntax Can someone tell me what the invalid syntax is here for this line? Appreciate any help you can give. (new python coder) Best, Jonathan

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Ubale to install Mediapipe
by aayushshah342＠gmail.com March 23, 2024

March 23, 2024

Unable to install mediapipe library on python version 3.12 Please help

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I need help with Django
by Iwuala Chibueze March 21, 2024

March 21, 2024

Dear Sir/Madam,I need complete details of running a inventory website with python Django. Kind Regards Chibueze Yahoo Mail: Search, Organize, Conquer

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Patching os.environ
by Albert-Jan Roskam March 19, 2024

March 19, 2024

Hi, What is the correct way of patching a dict in a test fixture? Below, MyTest1 fails, while MyTest2 succeeds. I thought the two tests were equivalent! Thanks! Albert-Jan import os import unittest from unittest.mock import patch class MyTest1(unittest.TestCase): def setUp(self): patcher = patch.dict(os.environ, {"FOO": "bar"}, clear=True) self.addCleanup(patcher.stop) def test_bla1(self): # why does this test fail? self.assertEqual(os.environ.get("FOO"), "bar") class MyTest2(unittest.TestCase): @patch.dict(os.environ, {"FOO": "bar"}, clear=True) def test_bla2(self): self.assertEqual(os.environ.get("FOO"), "bar") if __name__ == "__main__": unittest.main()

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MTG: Introductions to PyQt and DataClasses
by dn March 17, 2024

March 17, 2024

The Auckland Branch of NZPUG meets this Wednesday, 20 March at 1830 NZDT (0530 UTC, midnight-ish Tue/Wed in American time-zones), for a virtual meeting. Part 1: Learn the basics of PyQt with code examples. Hannan Khan is currently consulting as a Data Scientist for the (US) National Oceanic and Atmospheric Administration. He holds a Bachelor's degree in Neuroscience as well as a Masters in Computer Science. As a keen member of the PySprings Users' Group (Colorado), his contribution is part of a collaboration between our two PUGs. Part 2: Why use Dataclasses? - will be the question asked, and answered, by yours truly. After surveying a number of groups, it seems most of us know that Dataclasses are available, but we don't use them - mostly because we haven't ascertained their place in our tool-box. By the end of this session you will, and will have good reason to use (or not) Dataclasses! Everyone is welcome from every location and any time-zone. The NZPUG Code of Conduct applies. JetBrains have kindly donated a door-prize. Our BigBlueButton web-conferencing instance is best accessed using Chromium, Brave, Vivaldi, Safari, etc, (rather than Firefox - for now). A head-set will facilitate asking questions but text-chat will be available. Please RSVP at https://www.meetup.com/nzpug-auckland/events/299764049/ See you there! =dn, Branch Leader

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Re: [Tutor] MTG: Introductions to PyQt and DataClasses
by dn March 17, 2024

March 17, 2024

On 18/03/24 10:02, Jim Schwartz wrote: > Actually, I have a sleep disorder that requires me to keep a constant sleep schedule. Thats why I asked. At a weekend meeting, discussion swirled around topics such as the best way to learn/work, how much work we should attempt in one sitting, could/should I 'do more', and similar. One of the valuable observations is that most of us would benefit by improving our sleep-schedule and ensuring we do sleep for sufficient time (probably longer than current habit). -- Regards, =dn

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