How can debugging tools like print_r be effectively used to troubleshoot PHP code?

To effectively use debugging tools like print_r to troubleshoot PHP code, you can use it to print out the contents of variables at specific points in your code to see what values they hold. This can help you identify any unexpected or incorrect values that may be causing issues in your code. By using print_r strategically throughout your code, you can track the flow of data and pinpoint where the problem lies.

$variable = "Hello, World!";
print_r($variable);