How can variables be properly concatenated in PHP to avoid unexpected behavior?

Variables can be properly concatenated in PHP by using the dot (.) operator to combine them within a string. This ensures that the variables are concatenated in the correct order and prevents any unexpected behavior that may occur when using double quotes. By explicitly concatenating variables using the dot operator, you can ensure that the output is as expected.

// Proper concatenation of variables in PHP
$var1 = "Hello";
$var2 = "World";

echo $var1 . " " . $var2; // Output: Hello World