7. Order of evaluation

Precedence rules

The order in which operators are evaluated in an expression is known as precedence of operators.

operator description Example
() parentheses are evaluated first (2+5*3) - (5/6+2*4)
**  //  %  /  *  -  + arithmetic operations next (in order)  10-2**5 >= 10%7
<  <=   >   >=   ==   != then comparisons and membership operators  a > 9 and b in [1, 2, 3]
not negation operator next not (a > 9) or b == 2
and conjunction (and) next a > 9 or a < 0 and b > 1 
or disjunction (or) last a > 9 or a < 0 and b > 1 

 

Example: Let's evaluate the Boolean expression below for:

  • g = 12, b = True, and a = 17
  • g >= 90 or b and a > 10
  • (g >= 90) or (b and a > 100
  • (g >= 90) or (b and a > 100)
  • F or (T and F)
  • F or F