Regular mode modifier

Pattern modifier	Description
I	Represents the match in and pattern is not case-sensitive
M	Treat a pattern as multiple rows, using ^ and $ to indicate that any row can start or end with a regular expression
S	If you do not use this mode to fix the symbol, the "." In the meta-character The default cannot represent a newline symbol, and the string is treated as a single line
X	Whitespace in the representation pattern is ignored
E	The regular expression must be used in a function that preg_replace replace the string (speaking of this function)
A	Begins with a pattern string, which is equivalent to a meta-character ^
Z	Ends with a pattern string, equivalent to a meta-character $
U	The characteristics of regular expressions: is to compare "greed", using this mode modifier can cancel greedy mode

String str = "Abcheabcllo"= Str.replaceall ("(? i) ABC", ""); //Replace search ABC ignore case other modifiers same usage (? i) (? m) (? s) (? x) ... System.out.println (str); // Output Hello

Regular mode modifier