How to match regex over multiple lines
java, newline, regex
Solution
You need to use the `s` flag (not the `m` flag).
It's called the `DOTALL` option.
This works for me:
String input = "1stline\n2ndLINE\n3rdline";
boolean b = input.matches("(?is).*2ndline.*");
I found it here.
Note you must use `.*` before and after the regex if you want to use `String.matches()`.
That's because `String.matches()` attempts to match the entire string with the pattern.
(`.*` means zero or more of any character when used in a regex)
Another approach, found here:
String input = "1stline\n2ndLINE\n3rdline";
Pattern p = Pattern.compile("(?i)2ndline", Pattern.DOTALL);
Matcher m = p.matcher(input);
boolean b = m.find();
print("match found: " + b);
I found it by googling `"java regex multiline"` and clicking the first result.
(it's almost as if that answer was written just for you...)
There's a ton of info about patterns and regexes here.
If you want to match only if `2ndline` appears at the beginning of a line, do this:
boolean b = input.matches("(?is).*\\n2ndline.*");
Or this:
Pattern p = Pattern.compile("(?i)\\n2ndline", Pattern.DOTALL);
Problem
I have a body of text and I am trying to find a character sequence within it. `String.contains()` will not work so Im trying to use `String.matches` method and a regular expression. My current regex isn't working. Here are my attempts: ``` "1stline\r\n2ndline".matches("(?im)^1stline$"); // returns false; I expect true "1stline\r\n2ndline".matches("(?im)^1stline$") // returns false "1stline\r\n2ndline\r\n3rdline".matches("(?im)^2ndline$") "1stline\n2ndline\n3rdline".matches("(?im)^2ndline$") "1stline\n2ndline\n3rdline".matches("(?id)^2ndline$") ``` How should i format my regex so that it returns true?