Order of operations¶

• The order of evaluation depends on the rules of precedence.
• Python follows the same precedence rules for its mathematical operators that mathematics does.
• The acronym PEMDAS (or PEDMSA) is a useful way to remember the order of operations:

1. Parentheses have the highest precedence and can be used to force an expression to evaluate in the order you want. 2 * (3-1) is 4.

2. Exponentiation has the next highest precedence, so``3*1**3`` is 3.

3. Multiplication and both Division operators have the same precedence, which is higher than Addition and Subtraction, which also have the same precedence. So 2*3-1 yields 5.

4. Operators with the same precedence are evaluated from left-to-right. In algebra we say they are left-associative. So 6-3+2 yields 5.

   • Due to some historical quirk, an exception to the left-to-right left-associative rule is the exponentiation operator **

     • always use parentheses to force exactly the order you want when exponentiation is involved: