[Matlab] Order of precedence in computations

[gfd43tg]

Hello, here is a list of the order of precedence for computations when programming, at least in MATLAB

1. Parentheses (starting with innermost pair)
2. NOT (~) (left to right)
3. Arithmetic operations (left to right)
4. Relational operations (left to right)
5. AND (&)
6. OR (|)
7. Short-circuit AND (&&)
8. Short-circuit OR (||)

I was wondering if there is any rhyme or reason for this order, or is it just something that I need to have committed to memory?

 

[FactChecker]

Double check those rules, correct them, and then memorize them. They are fairly standard in programming and in mathematics. Be sure to check the rules you posted. Line 3 is wrong. It would make 2 + 3 * 5 = (2 + 3) *5 = 25. That is wrong. Multiplication precedes addition so 2 + 3 * 5 = 2 + 15 = 17.

Also, use parentheses liberally to force the calculation that you want.

 

[gfd43tg]

Great. I forgot an old trick for memorizing things, use mnemonics! PNARAOSS!

 

[kreil]

The rules are all here:

http://www.mathworks.com/help/matlab/matlab_prog/operator-precedence.html

 

[alphy]

I can say that there is indeed a rationale behind this order of precedence in computations. The purpose of this order is to ensure that mathematical expressions are evaluated in a consistent and predictable manner. By following this order, we can avoid ambiguity and potential errors in our calculations.

For example, if we did not have parentheses as the first priority, the expression (3+4)*5 could be interpreted as 3+(4*5) or (3+4)*5, resulting in two different outcomes. By giving parentheses the highest priority, we ensure that the innermost operations are evaluated first, leading to the correct result.

Similarly, the order of precedence for logical operations is designed to prioritize the evaluation of expressions in a way that makes sense and is consistent with mathematical principles. This allows us to write complex expressions without having to use excessive parentheses, making our code more readable and efficient.

In summary, the order of precedence in computations is not something you need to memorize, but rather something you should understand and apply in your coding. Knowing the rationale behind it can help you write more efficient and error-free code.