扫描仪长度不匹配！ java的

The string variable result has the following string:

字符串变量result具有以下字符串:

All Prime Numbers Up To {10}:
1 2 3 4 5 6 7 8 9

When I use this code to scan each numerical token and return its length:

当我使用此代码扫描每个数字标记并返回其长度时:

Scanner scan = new Scanner(result);
        while (scan.hasNext()) {
            String num = scan.next();
            if (num.matches(".*\\d.*")) {
                System.out.print("number:     ");
                System.out.println(num);
                System.out.print("The length: ");
                System.out.println(num.length());
                System.out.println("----");
            }
        }

The result shows the following:

结果显示如下:

Please Enter a Number: 9
number:     {9}:
The length: 4
----
number:     1
The length: 1
----
number:     2
The length: 10
----
number:     3
The length: 10
----
number:     4
The length: 1
----
number:     5
The length: 10
----
number:     6
The length: 1
----
number:     7
The length: 10
----
number:     8
The length: 1
----
number:     9
The length: 1
----

Why it is not printing the correct length of each token of numbers? Even though it prints it correctly!

为什么不打印每个数字标记的正确长度?即使它正确打印!

2 个解决方案

#1

How do you initialize the variable result?

如何初始化变量结果?

String result = "All Prime Numbers Up To {10}:\n1 2 3 4 5 6 7 8 9";

Using the init above I get a correct length of 1 for all numbers 1-9. I would use something like this:

使用上面的init,我得到所有数字1-9的正确长度1。我会用这样的东西:

String result = "All Prime Numbers Up To {10}:\n1 2 3 4 5 6 7 8 9";

Scanner scan = new Scanner(result);
while (scan.hasNext()) {
    if (scan.hasNextInt()) {
        Integer num = scan.nextInt();
        System.out.println("number: "+num);
        System.out.println("The length: "+num.toString().length());
        System.out.println("----");
    }
    else {
        scan.next();
    }
}
scan.close();

#2

I figured out the reason thanks to @KickButtowski. The problem was with my regex.

我想出了@KickButtowski的原因。问题在于我的正则表达式。

I had to change it to the following: "[0-9]+" then it worked!

我不得不将其更改为以下内容:“[0-9] +”然后它才有效!

Even though my previous code was not wrong, this regex solved another problem I had in my code. If I used the regex ".*\\d.*" it is going to return numbers that is mixed with characters, and I didn't want that.

即使我之前的代码没有错,这个正则表达式解决了我在代码中遇到的另一个问题。如果我使用正则表达式“。* \\ d。*”它将返回与字符混合的数字,我不想要那个。

#1