Question

I have a string which I’d like to remove the end of line characters from the very end of the string only using Java

"foo\r\nbar\r\nhello\r\nworld\r\n"

which I’d like to become

"foo\r\nbar\r\nhello\r\nworld"

(This question is similar to, but not the same as question 593671)

Answer 1

You can use s = s.replaceAll("[\r\n]+$", "");. This trims the \r and \n characters at the end of the string

The regex is explained as follows:

• [\r\n] is a character class containing \r and \n
• + is one-or-more repetition of
• $ is the end-of-string anchor

References

• regular-expressions.info/Anchors, Character Class, Repetition

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Related topics

You can also use String.trim() to trim any whitespace characters from the beginning and end of the string:

s = s.trim();

If you need to check if a String contains nothing but whitespace characters, you can check if it isEmpty() after trim():

if (s.trim().isEmpty()) {
   //...
}

Alternatively you can also see if it matches("\\s*"), i.e. zero-or-more of whitespace characters. Note that in Java, the regex matches tries to match the whole string. In flavors that can match a substring, you need to anchor the pattern, so it’s ^\s*$.

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