PHP Word Escape Considerations _php Tips

In php:

* PHP string with single quotation mark delimiter, support two escape \ ' and \
* A PHP string with double quotes as delimiters that supports the following escapes:
\ n line Wrap (LF or ASCII character 0x0A (10))
\ r Carriage return (CR or ASCII character 0x0D (13))
\ t Horizontal tab (HT or ASCII character 0x09 (9))
\ reverse Slash
\$ dollar Sign
\ "Double Quotes
\[0-7]{1,3} This regular expression sequence matches a character represented by a octal symbol
\x[0-9a-fa-f]{1,2} This regular expression sequence matches a character represented in hexadecimal notation

give a few examples:

An example that contains the special characters:

$str = "FFFF\0FFFF";
Echo (strlen ($STR));
Echo ("\ n");
For ($i =0 $i <strlen ($STR); $i + +) echo ("\ T". Ord ($str {$i}));
Echo ("\ n");

Output results:
----------------------

9
102 102 102 102 0 102 102 102 102

example of replacing special characters

$str = "FFFF\0FFFF";
$str = Str_replace ("\x0", "", $str);
or use $STR = Str_replace ("" "," ", $str);
or with $STR = Str_replace (chr (0), "", $str);
Echo (strlen ($STR));
Echo ("\ n");
For ($i =0 $i <strlen ($STR); $i + +) echo ("\ T". Ord ($str {$i}));
Echo ("\ n");
Output results:
----------------------
8
102 102 102 102 102 102 102 102


octal ASCII code example:

Note that the string that conforms to the regular \[0-7]{1,3} represents an octal ASCII code.
$str = "\0\01\02\3\7\10\011\08\8"; The \8 here are not compliant and are amended to "\\8" (ASCII is 92 and 56)
Echo (strlen ($STR));
Echo ("\ n");
For ($i =0 $i <strlen ($STR); $i + +) echo ("\ T". Ord ($str {$i}));
Echo ("\ n");
Output results:
----------------------
11
0 1 2 3 7 8 9 0 56 92 56

hexadecimal ASCII code example:

$str = "\x0\x1\x2\x3\x7\x8\x9\x10\x11\xff";
Echo (strlen ($STR));
Echo ("\ n");
For ($i =0 $i <strlen ($STR); $i + +) echo ("\ T". Ord ($str {$i}));
Echo ("\ n");
Output results:
----------------------
10
0 1 2 3 7 8 9 16 17 255