Regular Expression Replacements

 
<?
    $a = "Foo moo boo tool foo";
    $b = preg_replace("/[A-Za-z]oo\b/", "Got word: $0\n", $a);
    print $b;
?>

1.	$0 is set to the whole match, then $1, $2
2.	Converting Line Breaks
3.	preg_replace
4.	preg_replace
5.	preg_replace with index
6.	Pass a fourth parameter to preg_replace( ) to specify the maximum number of replacements you want to make.
7.	Pass arrays of regular expressions and replacement strings to preg_replace().
8.	Replacing with preg_replace()
9.	Using Back References with preg_replace()
10.	Using preg_replace() to Replace Patterns
11.	e modifier treats the replacement string in preg_replace() as if it were PHP.
12.	pass arrays as parameter one and parameter two, and preg_replace() performs multiple replaces
13.	Escape a > character in HTML
14.	Replacing URLs with Links
15.	Formatting a Phone Number
16.	Entity encoding matched text
17.	Escaping Special Characters
18.	Remove any doubled-up whitespace
19.	Replace any non-space whitespace, with a space
20.	Replace with regular expression
21.	Replacing using backreferences
22.	Quote escaping in backreference replacements

Regular Expression Replacements : preg_replace « String « PHP