Question

我正在尝试删除字符串中的每个数字，然后复制该数字后面的字母。例如，字符串4a2b应输出aaaabb。到目前为止，我的代码看起来像这样：

Scanner scan= new Scanner(System.in);
    String s = scan.nextLine();
    String newString = s.replace(" ", "");
    newString=newString.replaceAll("\\W+", "");
    newString=newString.replaceAll("\\d+", "");
    System.out.println(newString);

是否可以使用正则表达式和replaceAll来做到这一点？

Answer 1

尝试，

   String newString = "4a2b";
    String num = "";
    StringBuilder res = new StringBuilder();
    for (int i = 0; i < newString.length(); i++) {
        char ch = newString.charAt(i);

        if (Character.isDigit(ch)) {
            num += ch;

        } else if (Character.isLetter(ch)) {
            if (num.length() > 0) {
                for (int j = 0; j < Integer.parseInt(num); j++) {
                    res.append(ch);
                }
            }
            num="";
        }
    }
    System.out.println(res);

Answer 2

试试这个：

public static void main(String[] args)
{
    String str = "ae4a2bca";
    Matcher m = Pattern.compile("(\\d+)(.)").matcher(str);
    StringBuffer sb = new StringBuffer();
    while (m.find())
    {
        m.appendReplacement(sb, times("$2", Integer.parseInt(m.group(1))));
    }
    m.appendTail(sb);
    System.out.println(sb.toString());
}

private static String times(String string, int t)
{
    String str = "";
    for (int i = 0; i < t; ++i) str += string;
    return str;
}

复制字符串中的字符

2 个答案: