#🔒 Terminating code after wrong user input
wintry iron
!code
scarlet kindleBOT
hollow glade
oof it's too long for me to use that format
icy ore
!paste
scarlet kindleBOT
wintry iron
function at line 31
What's the question? Your original message was nuked.
hollow glade
oh!
why does my code terminate instead of asking the user to reinsert a valid input when I purposely assign a wrong (float / negative) value to n or k?
to test it
probably the case for p as well, but I haven't tried
wintry iron
First, know that isinstance(k, int) isn't a useful check. k for example is the direct result of a call to int, so it must contain an int. If the input wasn't valid, int would throw and the line under it would never be reached.
hollow glade
I suspected as much, I added it as an overkill measure because I was still getting that problem even before when isinstance(k, int) wasn't there
but it does seem useless
wintry iron
And how is the program terminating? Gracefully? An error?
A screenshot/copy of a buggy session would be good.
wintry iron
Line 52 isn't in a try.
hollow glade
ah! that must be it!
hollow glade
interesting. scenario 1 does work as expected...
also explains why I'm getting this
wintry iron
Ya, the error handling is only present in one branch. You would likely benefit from writing some standardized function to take and validate input so you don't need while loops with trys all over the place every time you need to take input.
It looks like the only actual validation (besides that int doesn't throw) is that the number is in a range, so maybe write a function with a signature like:
def get_validated_input(prompt: str, min_n: int, max_n: int) -> str:
And then this function handles the looping, try, range check, and returns the validated input.
hollow glade
I'm not too familiar with try-except blocks yet. Why am I still getting the problem where scenario 5 doesn't work? I thought I made it work the same way as 1-4
def get_user_input(scenario):
print(f"\nPlease provide the parameters for scenario {scenario}:")
if scenario in range(1, 4):
while True:
try:
n = int(input("Enter the value of n (number of trials): "))
if not (n >= 1):
raise ValueError("Invalid value for n. It must be a positive integer.")
k = int(input("Enter the value of k (number of successes): "))
if not (0 <= k <= n):
raise ValueError("Invalid value for k. It must be an integer between 0 and n.")
p = float(input("Enter the value of p (success rate): "))
if not (0 <= p <= 1):
raise ValueError("Invalid value for p. It must be between 0 and 1.")
break
except ValueError as e:
print(f"Invalid input: {e}")
return k, n, p
elif scenario in range(4, 7):
while True:
try:
n = int(input("Enter the value of n: "))
if not (n >= 1):
raise ValueError("Invalid value for n. It must be a positive integer.")
k = int(input("Enter the value of k: "))
if not (0 <= k <= n):
raise ValueError("Invalid value for k. It must be an integer between 0 and n.")
p_func = input("Enter the function p(n) or p(k) as a valid Python expression (e.g., 'lambda n: n/10'): ")
p_func = eval(p_func)
if not callable(p_func):
raise ValueError("Invalid input. Please enter a valid callable function.")
break
except (SyntaxError, NameError) as e:
print(f"Invalid input: {e}")
return k, n, p_func
else:
return None
I'll also try this. thanks
wintry iron
You aren't catching ValueError.
wintry iron
Also, catching SyntaxErrors is pretty sketchy. That has the potential to hide real bugs. If you really want to do that to handle eval failures (why are you using eval?), eval should have its own try that only wraps the call to eval.
Wait, actually, no it won't.
Still odd, but actual syntax errors will happen before the code runs.
hollow glade
i was wondering why I'm still catching those two errors. Since It's the first time i'm trying to work with try-except, I asked chatgpt for a template. It was the AI that added the eval function and error handling
wintry iron
i was wondering why I'm still catching those two errors. Since It's the first ti...
Holy shit.
Lol
hollow glade
I only have a vague understanding of how eval() works
hollow glade
Holy shit.
I'm not saying I didn't write the rest of the code myself x)
wintry iron
Exhibit One of why getting code from AI is bad.
hollow glade
i guess...
wintry iron
I only have a vague understanding of how eval() works
eval invokes the interpreter to run Python code while your program is running. It's pretty rare to need it.
hollow glade
okay, I just needed something that would allow me to create a function via user input
it's a binomial distribution and this would be the case where the success rate for the trials varies with either k or n
hollow glade
it's a binomial distribution and this would be the case where the success rate f...
r/unexpected korn
wintry iron
okay, I just needed something that would allow me to create a function via user ...
That somewhat sounds like a good use for eval. A better solution would be to use an actual parser/expression evaluator for your particular purpose, but that's complicated. Just know that if you're using eval, it should only ever run code that came from the current user. Running code taken from the disk or from the internet is dangerous.
hollow glade
okay, I just needed something that would allow me to create a function via user ...
this is mainly what i needed chatpgt for. It goes beyond my understanding
hollow glade
That somewhat sounds like a good use for `eval`. A better solution would be to u...
thanks for the heads up
scarlet kindleBOT
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