What are some best practices for handling and trimming whitespace in PHP strings to ensure accurate results?

When handling and trimming whitespace in PHP strings, it's important to use the appropriate functions to ensure accurate results. The trim() function can be used to remove whitespace from the beginning and end of a string, while rtrim() and ltrim() can be used to remove whitespace from the right and left sides, respectively. It's also important to be mindful of the type of whitespace being removed, as different characters like spaces, tabs, and newlines may need to be handled differently.

// Example of trimming whitespace from a string using trim()
$string = "   Hello, World!   ";
$trimmedString = trim($string);
echo $trimmedString;