Impatient | source examples to support Cascading | Runtime Evironment library

I am trying sample programs on Scala implicits. I am trying to implement one solution from the "Scala for the Impatient" book.

I have written as Fraction class having two member variables numerator and denominator with an operation overloading method "*(fraction)", so that we can call multiplication on Fraction objects like fration1 * fraction2 * fraction3.

Now, I tried to implement intToFraction and fractionToInt implicit methods, so that we can also write syntax like 2fraction13. I tried implementing those methods in companion object of Fraction class. But those methods are not getting called.

As suggested by Scala docs, Scala compiler will try to find out implicit implementation in the companion object. Here, we are performing operation on objects of Fraction class, so I assume, implicits declared in Fraction should have been called automatically. I also tried by importing implicit methods explicitly but it did not work.

Please find code snippet below for your reference.

I have website contact form that, when submitted, sometimes takes a few second to send.

The user, usually because they're impatient, clicks again. This results in the form being sent multiple times to the host.

To prevent this, I've tried implementing something along these lines, but thinking there's something cleaner and better:

I want to make a program with a recording and a stop button, and a label on top to show if it is still recording or done recording. I took the basic recording-code-structure from another question, there probably could be a mistake in how I rewrote it.

Now to my problem: the widow is opening and it looks like how I want it to look, but as soon as I click anything aftrer the 'record' button the program hangs itself (with the label changed to 'recording...'). One time I also waited about 10 minutes to see if I wasn't just too impatient the times before (that was not the problem) it goes until Windows says 'Python is not responding' because I clicked the exit button / too many times on the window.

before clicking -> recording, stop button clicked

working with: Python 3.10.1 & VSCode 1.63.2

Any help will really be appreciated!

I am writing a page that loads a PDF using the SelectPDF library. The problem I am running into is the load time for rendering the PDF. It takes like 2-3 seconds for the PDF to render from HTML.

This isn't an issue, but I want to disable the button used to create the pdf during that loading period. Because if the user gets impatient and clicks the button again, the process starts over.

I thought using a script manager and an update panel would allow me to do this, but I cannot seem to figure it out. I have partial page rendering and the update mode set to conditional, but when I call the update() method from my code, nothing happens. The button doesn't disable until the PDF finishes rendering.

I want to force the button enabled state to update before the PDF starts rendering, not after.

Here is my code

The ASPX page

Objective

Write a function values(f, low, high) that yields an array of function values [f(low), f(low + 1), . . ., f(high)].

What I Tried

In a big data scenario, where a piece of code has to run tens of thousands of times would checking the integrity of a value on an interface(using switch statements or if's, etc...) be faster than checking after inserting the values on a database with triggers(technically before they are inserted but in a human perspective as the trigger in this case would verify if everything right before entering the value)?

So basically me and a friend of mine had a shared interest over a topic which involved gathering huge amounts of data as the fluctuations we are trying to measure are very abstract and are only noticeable by the average joe over a long period of time.

The thing is no one is offering that data, so we decided to code some crawlers to gather the values for us. We're talking about thousands of "objects" with like 7-8 properties to extract and since we're not only broke but impatient, waiting is a undesirable option as the code might have to run over and over daily for us to gather anything resembling a useful extrapolation.

With this said while we were programming the interface in python to populate the PostgreSQL database i suggested that unit conversions should be done as a trigger since most of the time(50-80%) the data inserted wouldn't need to be converted.

I presumed that a trigger wouldn't "waste time" if a conversion wouldn't require a conversion since i think a trigger is a multi threaded procedure where one of the threads sleeps until something is triggered causing a small improvement in performance. I also remembered this chart that was presented in my classroom

althought this is a bit of a stretch as this pyramid is meant to be used to check integrity after the the tables are populated so it makes sense that a interface that not only has to connect to the database, read the columns, take a decision, and execute it would be the last thing to use.

My friends argument is that the time we would take to develop the triggers would be too excruciating, and time consuming. not only that but it would amplify the complexity which as we all know simple and obvious code is always desirable. Not only that but even if triggers worked on the best case scenario, like i said they would be multi threaded and would be able to be perfectly efficient, the same could be replicated in python with threads and it would still be faster.

His argument was solid especially the first part, since even if i suck with python, correcting, changing or even adding triggers with no graphical help when you're a noob like me can take forever so in the end even if i decided to scrap the python code it wouldn't be as big of a sacrifice as wasting time on a trigger that would run slower than if we just took the simple answer

Either way here's the code we ended up using:

I wanted my BASH script to end in a defined way doing some cleanup before exiting. It's easy to do if the script runs until end, but it's getting tricky if the user is impatient and sends a SIGINT (^C).

So I added a trap cleanup INT EXIT (cleanup is my function to clean things up), and I thought things were OK (as cleanup would be called when the script exits, cleanup itself does not use exit).

But then I started a test adding kill -INT $$; sleep 4 in the middle of the script, and I realized that cleanup is being called on SIGINT, but still the sleep 4 was executed and at the end of my script cleanup was called a second time, something I did not intend.

So I wanted to "reset" the handlers at the end of my cleanup using trap INT EXIT as the manual page said the syntax is "trap [-lp] [[arg] sigspec ...]" (also saying: "If arg is absent (and there is a single sigspec) or -, each specified signal is reset to its original disposition (the value it had upon entrance to the shell).").

Interestingly that did not work as intended, so I used trap '' INT EXIT instead (The manual says: "If arg is the null string the signal specified by each sigspec is ignored by the shell and by the commands it invokes."). It would be a nice sub-question how to do it correctly, but let's ignore that right now.

If I modify my trap to trap cleanup INT, then the cleanup is executed immediately when receiving the SIGINT, and not when the script exits after the sleep eventually (SIGINT does not cause the script to exit early).

If I modify my trap to trap cleanup EXIT, then the cleanup is executed immediately when receiving the SIGINT, and the script ends after cleanup returned.

So the question is: Does trap cleanup INT EXIT make any sense (for cleanup purposes)? It seems to me that EXIT includes the exits caused by any signal, too (I'm unsure whether that has been the case always). Contrary trapping SIGINT would perform cleanup actions without actually causing the script to exit.

Is there a general agreed-on "cleanup trap pattern"? (There is a similar question in bash robustness: what is a correct and portable way to trap for the purpose of an "on exit" cleanup routine?, but it has no good answer)

I am trying to save some quotes from a csv file to my django model using python manage.py shell because I could not use django-import-export to do it. I asked about it at Tags imported but relationship not imported with django-import-export but nobody answered and I could not find more things to try after googling.

After reading the documentation and previous answers here about django querysets and tagging, I managed to save most of each quote but the tags are not saved. The query set does not return tags field, which causes the AttributeError. Please see shell output q: below

My tag model follows https://docs.wagtail.io/en/stable/reference/pages/model_recipes.html#custom-tag-models. From django-admin, the relationships are working. So the missing piece of the puzzle is saving the tags. What query should I use to locate the tags field or what method should I use to save the tags?

#The script I'm trying to run in python manage.py shell