OCP 7Ⅱ正则表达式

Question

import java.util.regex.*;

public class Regex2 {

    public static void main(String[] args) {
        Pattern p = Pattern.compile("\\d*");
        Matcher m = p.matcher("ab34ef");
        boolean b = false;
        while ( m.find()) {
            System.out.print(m.start() + m.group());
        }
    }
}

此代码产生输出的原因: 01234456

Answer 1

\d* means integer 0 or more times.So an empty string between a and b ,before a ...those are also

matched.Use `\d+` to get correct result.

见演示。

https://www.regex101.com/r/fG5pZ8/25

Answer 2

因为\\d*表示零或更多位数。

作为，

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