What are some best practices for efficiently manipulating and modifying text strings in PHP?

When manipulating and modifying text strings in PHP, it is important to use built-in functions and methods efficiently to achieve the desired result. Some best practices include using functions like `strlen()` to get the length of a string, `substr()` to extract parts of a string, `str_replace()` to replace specific substrings, and `trim()` to remove whitespace. Additionally, using concatenation (`.`) to combine strings and regular expressions for more complex string manipulation can also be helpful.

// Example: Using str_replace() to replace a substring in a string
$string = "Hello, World!";
$new_string = str_replace("Hello", "Goodbye", $string);
echo $new_string;