Constructing regex pattern to match sentence

Question

I'm trying to write a regex pattern that will match any sentence that begins with multiple or one tab and/or whitespace. For example, I want my regex pattern to be able to match " hello there I like regex!" but so I'm scratching my head on how to match words after "hello". So far I have this:

    String REGEX = "(?s)(\\p{Blank}+)([a-z][ ])*";
    Pattern PATTERN = Pattern.compile(REGEX);
    Matcher m = PATTERN.matcher("         asdsada  adf adfah.");
    if (m.matches()) {
        System.out.println("hurray!");
    }

Any help would be appreciated. Thanks.

Answer 1

An example regex to match sentences by the definition: "A sentence is a series of characters, starting with at lease one whitespace character, that ends in one of ., ! or ?" is as follows:

\s+[^.!?]*[.!?]

Note that newline characters will also be included in this match.

Answer 2

A sentence starts with a word boundary (hence \b) and ends with one or more terminators. Thus:

\b[^.!?]+[.!?]+

https://regex101.com/r/7DdyM1/1

This gives pretty accurate results. However, it will not handle fractional numbers. E.g. This sentence will be interpreted as two sentences:

The value of PI is 3.141...