Comment on I dunno

• Feathercrown@lemmy.world ⁨3⁩ ⁨days⁩ ago

  Uh, no. I don’t think you’ve thought this through, or you’re just using (AS) without realizing it. Conversations around operator precedence can cause real differences in how expressions are evaluated and if you think everyone else is just being pedantic or is confused then you might not underatand it yourself.

  Take for example the expression 3-2+1.

  With (AS), 3-2+1 = (3-2)+1 = 1+1 = 2. This is what you would expect, since we do generally agree to evaluate addition and subtraction with the same precedence left-to-right.

  With SA, the evaluation is the same, and you get the same answer. No issue there for this expression.

  But with AS, 3-2+1 = 3-(2+1) = 3-3 = 0. So evaluating A with higher precedence rather than equal precedence yields a different answer.

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  • SmartmanApps@programming.dev ⁨3⁩ ⁨days⁩ ago

    Some other pedantic notes you may find interesting

    It’s hilarious that you added in this in afterwards, hoping I wouldn’t see it so you could claim the last word 😂

    There is no “correct answer” to an expression without defining the order of operations on that expression

    There is only one order of operations, defined in many Maths textbooks.

    Addition, subtraction, etc. are mathematical necessities that must work the way they do

    Hence the order of operations rules, found in Maths textbooks

    But PE(MD)(AS) is something we made up

    PEMDAS actually, and yes, it’s only a convention, not the rules themselves

    there is no actual reason why that must be the operator precedence rule we use

    That’s why it’s only a convention, and not a rule.

    this is what causes issues with communicating about these things.

    Nope, doesn’t cause any issues - the rules themselves are the same everywhere, and all of the different mnemonics all work

    Your second example, -1+3+2=4, actually opens up an interesting can of worms

    No it doesn’t

    so subtraction is a-b

    Just -b actually

    negation is -c

    Which is still subtraction, from 0, because every operation on the numberline starts from 0, we just don’t bother writing the zero (just like we don’t bother writing the + sign when the expression starts with an addition).

    a two-argument definition of subtraction

    Subtraction is unary operator, not binary. If you’re subtracting from another number, then that number has it’s own operator that it’s associated with (and might be an unwritten +), it’s not associated with the subtraction at all.

    you can also define -1 as a single symbol

    No you can’t. You can put it in Brackets to make it joined to the minus sign though, like in (-1)²=1, as opposed to -1²=-1

    not as a negation operation followed by a positive one

    The 1 can’t be positive if it follows a minus sign - it’s the rule of Left Associativity 😂

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    These distinctions are for the most part pedantic formalities

    No, they’re just you spouting more wrong stuff 😂

    you could argue that -1+3+2 evaluated with addition having a higher precedence than subtraction is -(1+3+2) = -6

    No, you can’t. Giving addition a higher priority is +(3+2)-1=+5-1=4, as per Maths textbooks…

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    Isn’t that interesting?

    No, all of it was wrong, again 😂

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  • SmartmanApps@programming.dev ⁨3⁩ ⁨days⁩ ago

    you’re just using (AS) without realizing it

    as per the textbooks 🙄

    Conversations around operator precedence can cause real differences in how expressions are evaluated

    No they can’t. The rules are universal

    you might not underatand it yourself

    says someone about to prove that they don’t understand it… 😂

    With (AS), 3-2+1 = (3-2)+1 = 1+1 = 2

    Nope! With AS 3-2+1=+(3+1)-(2)=4-2=2

    This is what you would expect

    Yes, I expected you to not understand what AS meant 😂

    since we do generally agree to evaluate addition and subtraction with the same precedence left-to-right

    It’s only a convention, not a rule, as just proven

    With SA, the evaluation is the same

    No it isn’t. With SA 3-2+1=-(2)+(3+1)=-2+4=2

    you get the same answer

    Yep, because order doesn’t matter 🙄 AS and SA both give the same answer

    No issue there for this expression

    Or any expression

    But with AS, 3-2+1 = 3-(2+1)

    You just violated the rules and changed the sign of the 1 from a + to a minus. 🙄 -(2+1)=-2-1, not -2+1. Welcome to how you got a wrong answer when you wrongly added brackets to it and mixed the different signs together

    So evaluating addition with higher precedence rather than equal precedence yields a different answer

    No it doesn’t., as already proven. 3-2+1=+(3+1)-(2)=+4-2=2, same answer 🙄

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    • Feathercrown@lemmy.world ⁨3⁩ ⁨days⁩ ago

      Oh, it’s you. I really want to have a good discussion about this, but it is not possible with your debate style. Once again, fragmenting your opponent’s argument into a million partial statements and then responding to those is ineffective for several reasons:

      1. You fail to understand the argument your opponent is making, and so you do not learn anything by engaging with it. You must first understand to learn.

      2. By divorcing each partial statement from its surrounding context, you are likely to change its meaning, so you are no longer even responding to the meaning of what was said.

      3. You are not making a point of your own, which means you are less likely to figure out your own mental model. You are simply stating facts, opinions, or misunderstandings as if they are self-evidently true, without knowing why you believe them to be true.

      4. Expanding on point three, it’s very easy to state two contradictory things without realizing it. For example, “No they can’t. The rules are universal” and “It’s only a convention, not a rule, as just proven”.

      5. Also expanding on point three, this also makes it hard for people to find the mistakes you’re making and correct them, because mistakes in your mental model are only visible through the statements you choose to make, which are incoherent when taken together. For example, I can see that you don’t fully understand what I mean by “operator precedence”, but this is not obvious from your main point, because you have no main point, because you do not understand what mine is.

      6. If your opponent also used this debate style, the argument takes hours and ends up entirely divorced from the initial meaning, completely destroying any hope of having the debate provide any actual value, ie. greater understanding.

      Please do not take these as insults; it’s a long shot to fundamentally change someone’s perspective like this in one post, but I would love if you saw the beauty of discussion.

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      • SmartmanApps@programming.dev ⁨3⁩ ⁨days⁩ ago

        I really want to have a good discussion about this

        says person who deleted their previous post when I proved how wrong it was 😂

        it is not possible with your debate style

        There’s no debate - the rules are in Maths textbooks, which you want to pretend don’t exist

        You fail to understand the argument your opponent is making

        You haven’t got one. That’s why you keep pretending Maths textbooks don’t exist

        By divorcing each partial statement from its surrounding context

        says person who deleted one of their posts to remove the context. 😂 The context is the rules of Maths, in case you needed to be reminded 😂

        you are likely to change its meaning

        Nope. I’m still talking about the rules of Maths 😂

        You are not making a point of your own

        Ok, so here you are admitting to comprehension problems. Which part did you not understand in addition and subtraction can be done in any order? 😂

        You are simply stating facts, opinions, or misunderstandings as if they are self-evidently true

        You left out backing it up with textbook screenshots and worked examples 😂

        without knowing why you believe them to be true.

        There’s no belief involved. It’s easy enough to prove it yourself by doing the Maths 😂

        it’s very easy to state two contradictory things without realizing it

        And yet I never have. Why do you think that is? 😂

        “No they can’t. The rules are universal”

        Which is correct

        “It’s only a convention, not a rule, as just proven”

        Which is also correct, and in no way contradicts the previous point, and I have no idea why you think it does! 😂 The first point is about the rules, and the second point is about conventions, which isn’t even the same thing

        this also makes it hard for people to find the mistakes

        That’s because I’m not making any 😂

        I can see that you don’t fully understand what I mean by “operator precedence”

        Says person who in their other post claimed “addition first” for -1+3+2 is -(1+3+2) = -6, and not +(3+2)-1=4 😂

        If your opponent also used this debate style,

        Which you don’t, given you have no evidence whatsoever to back up your points with 😂

        ends up entirely divorced from the initial meaning

        I’ve been on-point the whole time, and you keep trying to deflect from how wrong your statements are 😂

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        Please do not take these as insults

        Well, obviously not, given I just proved they were all wrong 😂

        allows you to understand why people know the brackets matter.

        Except I’ve proven, repeatedly, that they don’t, and so now you’re trying to deflect from that (and deleted one of your posts to hide the evidence of how wrong you are) 😂

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