Regex expression to capture only words without numbers or symbols

Question

I need some regex that given the following string:

"test test3 t3st test: word%5 test! testing t[st"

will match only words in a-z chars:

Should match: test testing

Should not match: test3 t3st test: word%5 test! t[st

I have tried ([A-Za-z])\w+ but word%5 should not be a match.

Answer 1

You may use

String patt = "(?<!\\S)\\p{Alpha}+(?!\\S)";

See the regex demo.

It will match 1 or more letters that are enclosed with whitespace or start/end of string locations. Alternative pattern is either (?<!\S)[a-zA-Z]+(?!\S) (same as the one above) or (?<!\S)\p{L}+(?!\S) (if you want to also match all Unicode letters).

Details:

• (?<!\\S) - a negative lookbehind that fails the match if there is a non-whitespace char immediately to the left of the current location
• \\p{Alpha}+ - 1 or more ASCII letters (same as [a-zA-Z]+, but if you use a Pattern.UNICODE_CHARACTER_CLASS modifier flag, \p{Alpha} will be able to match Unicode letters)
• (?!\\S) - a negative lookahead that fails the match if there is a non-whitespace char immediately to the right of the current location.

See a Java demo:

String s = "test test3 t3st test: word%5 test! testing t[st";
Pattern pattern = Pattern.compile("(?<!\\S)\\p{Alpha}+(?!\\S)");
Matcher matcher = pattern.matcher(s);
while (matcher.find()){
    System.out.println(matcher.group(0)); 
} 

Output: test and testing.

Answer 2

Try this

Pattern tokenPattern = Pattern.compile("[\\p{L}]+");

[\\p{L}]+ this prints group of letters