Notes on php character escaping

$str = "ffff
-----------------------

9
102 102 102 102 0 102 102 102 102

2. Examples of replacing special characters

$str = "ffff ----------------------- 8 102 102 102 102 102 102 102 102

Three, octal ascii code example:

//Note that a string that conforms to the regular pattern [0-7]{1,3} represents an octal ASCII code.
$str = "
-----------------------
11
0 1 2 3 7 8 9 0 56 92 56

4. Example of hexadecimal ascii code: