java 一组扫描单词串并提取第一个或最后一个单词的方法。

Posted 2021-05-08

import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.Scanner;

public class classify {
    public static void main(String[] args) {
        System.out.println(isoneword("ok?"));
    }
    //checks for question mark at tail of the string.
    public static boolean isquestion(String phrase) {
        Pattern question = Pattern.compile("^.*[?]$");
        Matcher findq = question.matcher(phrase);
        return findq.matches();
    }
    //gets the first word in a string.
    public static String getfirstword(String phrase) {
        Pattern temp = Pattern.compile("^([a-z]+) .*$");
        Matcher first = temp.matcher(phrase);
        if (first.find()) {
            return first.group(1);
        }
        return "no match";
    }
    //gets the last word in a string
    public static String getlastword(String phrase) {
        Pattern temp = Pattern.compile("^.* ([a-z]+)$");
        Matcher last = temp.matcher(phrase);
        if (last.find()) {
            return last.group(1);
        }
        return "no match";
    }
    //determines if a string consists of a single word
    public static boolean isoneword(String phrase) {
        Pattern temp = Pattern.compile("^[a-z!?.]+$");
        Matcher word = temp.matcher(phrase);
        return word.matches();
    }
}