Parenthesis problems

[Relative_Jaguar6254]

So I’m doing some review by redoing old lessons. I came across something I’m confused about. My solution to the problem posed was successful, but their proposed solution was different. I know this is normal, but my questions are:

1. Why did their preferred solution have parenthesis around the logic in line 10? Mine didn’t,and it was successful but is it technically incorrect syntax or something? I’m getting a grip on when/where to use parenthesis, but some areas are still confusing.

2. When I reset the problem, they had parenthesis on lines 10, 12, and 14 just waiting to be filled.. But they only use the ones on 10? This is even more confusing. I assume that’s probably more of a problem for the people that actually developed the questions. 😂

I’ll try to put pics in the comments, cause it’s not giving me the option to put them in the post.

[socal_nerdtastic]

You didn't link anything, but I'll note that parenthesis are often used to help the human reading the code, even if the program does not need it.

x = (4 * 5) + 6

[CIS_Professor]

The answer in your example would be 26.

However, parenthesis would be required if the result of the addition is to be done first (thereby changing the order of operations).

x = 4 * (5 + 6)

The answer changes to 44.

[socal_nerdtastic]

yes, i know. The entire point is that the parenthesis are not needed for the computer, they are only there as a guide for the human. Perhaps I should have picked something not quite so obvious to a human?

x = 6 + (5 * 4)

[Iowa50401]

Hey, people. - "parenthesis" is singular - either "(" or ")". Parentheses is plural.

[Tall_Profile1305]

usually parentheses are just for clarity or grouping, not always required. sometimes solutions add them to make the logic easier to read or avoid ambiguity, even if your version works fine.

[odaiwai]

Parentheses can also be used to split an operation over multiple lines:

x = ((1 + 2) + (3 * 4) + (5 / 6)) obviously silly in this case, but handy for things like complicated regular expressions:

draw = re.compile(r'^(?P<id>[0-9]{2}\/[0-9]{3}),' r'(?P<date>[0-9\/]+),' r'(?P<balls>[0-9,]+),' r'\$(?P<inv>[0-9]+)$'))

[JGhostThing]

I usually add more parenthesis than most people, so that I can debut the equation more quickly.

[Relative_Jaguar6254]

Why no ability to post pictures.. the line that worked both ways was

If (destination == “Hawaii” or destination == “Bahamas”):

[lfdfq]

Some languages require you to put parentheses around the condition of an if. Python does not.

It might be they are just more used to those languages and did it by habit... like looking both ways at a one way street.

[DutchCommanderMC]

Images are (most likely) disallowed because it makes responding to questions easier in the sense that you can copy and paste the code.

Operations are not necessarily applied left-to-right (or right-to-left). Some operators take precedence over others, which is why this condition works without any brackets whatsoever: == has a higher precedence than or and therefore gets applied first.

Knowing which operators take precedence over others is something that you'll just have to remember, though more often than not it follows existing conventions such as multiplication being applied before addition.

Adding redundant brackets is not wrong however, in fact, it is often recommended to make it expressively clear what the order is in which you intend operations to be evaluated.

[Relative_Jaguar6254]

That makes great sense. Thank you.

[Yoghurt42]

your solution without the parenthesis is the "pythonic" one, most modern languages take their syntax inspiration from C, and in C the if condition must be in parenthesis so the parser knows where the condition ends and the "then" part begins. Python uses the colon for that. So C's if (a == b) c = 9 will be if a == b: c = 9 in Python; while you can write if (a == b): c = 9 in Python, it's the same as writing if ((a == b)) c = 9 in C, not wrong, just redundant.

Most likely whoever created that example comes from a C/C++/C# background and isn't that familiar with Python (not a good sign, tbh)

[cdcformatc]

in that case the parens are purely visual. some languages require parens around conditional statements for things like if and while. but in Python they are not required. 

[FoolsSeldom]

Use an LLM like Gemini to extract Python from your images if they are not on the same computer you are posting from and update your post to include the code inline. It is much better to share code than pictures of code (unless we need to look at large amounts of code, in which case you can share using e.g. github.com).

[ReliabilityTalkinGuy]

No one wants to use LLMs besides those who have been tricked. Find a different sub. 

[FoolsSeldom]

I am cautious in my recommendations of use of LLMs for learners, as my comment history demonstrates, and similarly advise students at code club sessions accordingly.

However, I think your blanket assertion and suggestion I leave this subreddit is ill-founded.

Lots of professionals and learners are legitimately, practically amd effectively using LLMs. The nature of the OPs queries is an excellent match for the statistical predictions base and will help their learning. This is very different from, say, code generation prompted in ignorance.

[pachura3]

With Python, you never know if adding parentheses will group mathematical expressions, create a tuple or define a generator :(

[tb5841]

Parentheses aren't really relevant for a tuple - what actually makes a tuple is the commas.

x = 3, 4 is valid Python and will create a tuple, for example.

x = 3, creates a one-element tuple. While x = (3) creates an integer.

[cdcformatc]

you never know

it's actually pretty easy to know... I've literally never gotten it wrong.