When you need to apply reversible ROT13 letter substitution, it helps to understand both the normal result and what changes with different inputs. This guide focuses on practical examples rather than repeating PHP background material.
str_rot13 provides the behavior described below. Latin A-Z letters rotate by thirteen positions; digits and punctuation remain unchanged.
What Is str_rot13 in PHP?
Apply reversible rot13 letter substitution. Latin A-Z letters rotate by thirteen positions; digits and punctuation remain unchanged.
Its syntax is:
str_rot13(string $string): string
Parameters and return value: Read the argument names and optional values in the signature above. Methods use an existing object, while stand-alone functions take direct arguments. The examples demonstrate the relevant arguments and the value returned or the object modified.
Important: ROT13 is not encryption and offers no protection for confidential information.
Example 1: Basic Usage
This first example demonstrates how to apply reversible ROT13 letter substitution with a small input.
<?php
echo str_rot13("Hello");
Output:
Uryyb
The example uses the simplest useful form. Latin A-Z letters rotate by thirteen positions; digits and punctuation remain unchanged. The output may depend on the active ICU locale, PHP configuration, or input supplied to the function.
Example 2: Another Case
Here the input or option changes, making it easier to see where the behavior differs. ROT13 is not encryption and offers no protection for confidential information.
<?php
$encoded = str_rot13("Secret 42!");
echo str_rot13($encoded);
Output:
Secret 42!
Compare the result to the first example. Use encryption APIs for secrecy; strrev() merely reverses byte order.
Practical Example: Applying the Function
This standalone example shows how the same operation fits into a small application task.
<?php
$labels = ["Internal", "External"];
foreach ($labels as $label) {
echo str_rot13($label) . PHP_EOL;
}
Output:
Vagreany
Rkgreany
The example keeps the operation visible and gives you a starting point for using it in an application. ROT13 is not encryption and offers no protection for confidential information.
Important Behavior and Edge Cases
- Core behavior: Latin A-Z letters rotate by thirteen positions; digits and punctuation remain unchanged.
- Return value: Check the result separately from changes to passed-in arrays, iterators, or object state.
- Data constraints: ROT13 is not encryption and offers no protection for confidential information.
- Environment: Run this example under a PHP version supporting the API; check results and exceptions before using them.
Comparison With Related Functions
| Function or Approach | When to Use It |
|---|---|
str_rot13 | Apply reversible rot13 letter substitution. |
| Related PHP APIs | Use encryption APIs for secrecy; strrev() merely reverses byte order. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
| Assuming the function works on every kind of input | Follow the declared argument types and check the input format before calling it. |
| Ignoring the behavior of the result | ROT13 is not encryption and offers no protection for confidential information. |
| Using the wrong related PHP API | Use encryption APIs for secrecy; strrev() merely reverses byte order. |
Key Takeaways
str_rot13helps you apply reversible ROT13 letter substitution.- Latin A-Z letters rotate by thirteen positions; digits and punctuation remain unchanged.
- ROT13 is not encryption and offers no protection for confidential information.
- Use encryption APIs for secrecy; strrev() merely reverses byte order.
str_rot13 is useful when you need to apply reversible ROT13 letter substitution. Start with the small examples, then adapt the practical example while respecting its input and environment requirements.