How do i check if string contains char sequence and backslash "\"?

Question

I'm trying to get true in the following test. I have a string with the backslash, that for some reason doesn't recognized.

String s = "Good news\\ everyone!";
Boolean test = s.matches("(.*)news\\.");
System.out.println(test);

I've tried a lot of variants, but only one (.*)news(.*) works. But that actually means any characters after news, i need only with \.

How can i do that?

With `"\\."`, you are trying to match a `.` symbol, not a ``\``. Use `s.matches(".*news\\\\.*")` — Wiktor Stribiżew, Apr 18 '17 at 13:55
Possible duplicate of [What is the backslash character (\\‌)?](http://stackoverflow.com/questions/12091506/what-is-the-backslash-character) — Alex, Apr 18 '17 at 13:59

score 2 · Answer 1 · answered Apr 18 '17 at 14:07

2

Group the elements at the end:(.*)news\\(.*)

answered Apr 18 '17 at 14:07

Abhishek Kumar

197
2
15

score 1 · Answer 2 · answered Apr 18 '17 at 13:57

1

You can use this instead :

Boolean test = s.matches("(.*)news\\\\(.*)");

answered Apr 18 '17 at 13:57

Youcef LAIDANI

55,661
15
90
140

score 0 · Answer 3 · answered Apr 18 '17 at 13:57

Try something like:

Boolean test = s.matches(".*news\\\\.*");

Here .* means any number of characters followed by news, followed by double back slashes (escaped in a string) and then any number of characters after that (can be zero as well).

With your regex what it means is:

.* Any number of characters
news\\ - matches by "news\" (see one slash)
. followed by one character.

which doesn't satisfies for String in your program "Good news\ everyone!"

score 0 · Answer 4 · answered Apr 18 '17 at 13:57

You are testing for an escaped occurrence of a literal dot: ".".

Refactor your pattern as follows (inferring the last part as you need it for a full match):

String s = "Good news\\ everyone!";
System.out.println(s.matches("(.*)news\\\\.*"));

Output

true

Explanation

The back-slash is used to escape characters and the back-slash itself in Java Strings
In Java Pattern representations, you need to double-escape your back-slashes for representing a literal back-slash ("\\\\"), as double-back-slashes are already used to represent special constructs (e.g. \\p{Punct}), or escape them (e.g. the literal dot \\.).
String.matches will attempt to match the whole String against your pattern, so you need the terminal part of the pattern I've added

score 0 · Answer 5 · answered Apr 18 '17 at 13:57

0

you can try this :

String s = "Good news\\ everyone!";
Boolean test = s.matches("(.*)news\\\\(.*)");
System.out.println(test);

answered Apr 18 '17 at 13:57

RAJNIK PATEL

1,039
1
17
30

How do i check if string contains char sequence and backslash "\"?

5 Answers5