What is the difference between == and === in PHP and how does it affect variable comparisons?

In PHP, the == operator checks if two variables are equal in value, while the === operator checks if two variables are equal in value and data type. This means that with ===, not only the values need to match, but also the data types must be the same. This can affect variable comparisons by ensuring a more strict and accurate comparison.

// Using === to compare variables with strict data type checking
$var1 = 5;
$var2 = "5";

if ($var1 === $var2) {
    echo "Variables are equal in value and data type";
} else {
    echo "Variables are not equal in value or data type";
}