java - 如何检查并显示其他两个特定单词之间的单词？

Question

用户将输入一个包含两个“bread”单词的字符串值。我的程序将打印给定字符串中第一次和最后一次出现“bread”之间的字符串，或者打印“There is no Sandwich!”如果没有两片面包。例如，对于输入“breadlolbread”，输出应为“lol”。

String a = "There is no sandwich!";

for (int i =0;i<len-3;i++) {
    if ((s.charAt(i)== 'b')&&(s.charAt(i+1)== 'r')&&(s.charAt(i+2)== 'e')&&(s.charAt(i+3)== 'a')&&(s.charAt(i+4)== 'd')) {

    }   
}

Answer 1

你可以这样做:

  public static void main(String[] args) {
        String text = "There are two bread which are very cool bread.";
        String bread = "bread";
        //make a new string by taking everything from first index of bread string+length of a bread string word and the last index of bread.
        String inBEtween = text.substring(text.indexOf(bread)+bread.length(), text.lastIndexOf(bread));
        //if the length inbetween trimmed of leading and tailing whitespace is greater than 0, print inBetween, otherwise print "No sandwich".
        if (inBEtween.trim().length() > 0) {
            System.out.println(inBEtween);
        } else {
            System.out.println("No sandwich.");
        }
    }

当然，您也可以使用正则表达式来做到这一点

 public static void main(String[] args) {
        String text = "There are two bread bread.";
        String pattern = "(?<=bread)(.*)(?=bread)";
        Pattern r = Pattern.compile(pattern);
        Matcher m = r.matcher(text);
        if (m.find()) {
            System.out.println(m.group());
        } else {
            System.out.println("No sandwich");
        }
  }