How does operator precedence and associativity affect the evaluation of expressions in PHP?

Operator precedence and associativity determine the order in which operators are evaluated in an expression. If not considered carefully, the result of the expression may not be as expected. To ensure the correct evaluation of expressions, it is important to understand the precedence and associativity of operators in PHP.

// Example of using parentheses to control the order of evaluation
$result = (5 + 2) * 3; // This will first add 5 and 2, then multiply the result by 3
echo $result; // Output: 21