正则表达式从段落中查找包含特定单词（java）的句子

Question

I have a list of words: dog , cat , leopard .

I'm trying to come up with a regex in Java to pull out the sentence from a long paragraph that contains any one of the words (case insensitive). The sentence ends in . ? or ! Could anyone help? Thank you!

Answer 1

The following assumes a sentence starts with a capital letter, and that there are no . , ! or ? in the sentence, apart from at the end of it.

String str = "Hello. It's a leopard I think. How are you? It's just a dog or a cat. Are you sure?";
Pattern p = Pattern.compile("[A-Z](?i)[^.?!]*?\\b(dog|cat|leopard)\\b[^.?!]*[.?!]");
Matcher m = p.matcher(str);

while (m.find()) {
    System.out.println(m.group());
}
// It's a leopard I think.
// It's just a dog or a cat.

Answer 2

Assumptions

• Sentence must start with a capital letter with no line terminators [.?!] in between.
• Keyword match is case insensitive. A sub-string match is not valid though.
• Keywords may appear anywhere in (start, end or in the middle of) the sentence.
• Supports quotations and informal double punctuation. Use the second regex if not required.

public class SentenceFinder {

    public static void main(String[] args) {
        String paragraph = "I have a list of words to match: dog, cat, leopard. But blackdog or catwoman shouldn't match. Dog may bark at the start! Is that meow at the end my cat? Some bonus sentence matches shouldn't hurt. My dog gets jumpy at times and behaves super excited!! My cat sees my goofy dog and thinks WTF?! Leopard likes to quote, \"I'm telling you these Lions suck bro!\" Sometimes the dog asks too, \"Cat got your tongue?!\"";
        Pattern p = Pattern.compile("([A-Z][^.?!]*?)?(?<!\\w)(?i)(dog|cat|leopard)(?!\\w)[^.?!]*?[.?!]{1,2}\"?");
        Matcher m = p.matcher(paragraph);
        while (m.find()) {
            System.out.println(m.group());
        }
    }
    /* Output:
       I have a list of words to match: dog, cat, leopard.
       Dog may bark at the start!
       Is that meow at the end my cat?
       My dog gets jumpy at times and behaves super excited!!
       My cat sees my goofy dog and thinks WTF?!
       Leopard likes to quote, "I'm telling you these Lions suck bro!"
       Sometimes the dog asks too, "Cat got your tongue?!"
    */
}

Simplified regex if "Quotes?!" (or informal punctuation) isn't required:
"([AZ][^.?!]*?)?(?<!\\\\w)(?i)(dog|cat|leopard)(?!\\\\w)[^.?!]*?[.?!]"

To fetch those sentences as well that don't start with a capital letter (if the input may have such typos):
"(?i)([az][^.?!]*?)?(?<!\\\\w)(dog|cat|leopard)(?!\\\\w)[^.?!]*?[.?!]"

Answer 3

this should do it. you just have to populate what words you want in the middle. example:

hello there i am a dog and i love to do things? Don't take my weakness for kindness. My bark is better than the bite of a leapord! So adopt me over another animal. Like a cat.

matches:

hello there i am a dog and i love to do things? My bark is better than the bite of a leapord! Like a cat. and do that (?i) to ignore case. i didn't put it in because i don't really remember syntax but someone else wrote it

"(?=.*?\\.)[^ .?!][^.?!]*?(dog|cat|leapord).*?[.?!]"

Answer 4

try this regex

   str.matches("(?i)(^|\\s+)(dog|cat|leopard)(\\s+|[.?!]$)");

(?i) is a special construct that means case insensitive

Answer 5

. (cat|dog|leopard). (\\.|\\?|\\!)$ and you should use the CASE_INSENSITIVE option of java.util.regex.Pattern.