扫描仪，使用Delimiter [英] Scanner, useDelimiter

问题描述

我在使用Scanner类中的useDelimiter时遇到一些问题。

I encounter some problem when using useDelimiter from the Scanner class.

Scanner sc = new Scanner(System.in).useDelimiter("-");
while(sc.hasNext())
{
    System.out.println(sc.next());
}

如果我有这个输入

ABC

A-B-C

输出将

AB

A B

并等到我输入另一个 - 表示打印出来最后一个字符

and wait until I type in another "-" for it to print out the last character

但是，如果我没有用户输入数据，而是将字符串插入扫描程序，则代码将起作用。它是什么原因，我该如何解决？我不想使用StringTokenzier

However if I instead of having user input data, and insert a String to the Scanner instead the code will work. What's the reason for it, and how do I fix it? I don't want to use StringTokenzier

推荐答案

如果扫描仪没有等你输入另一个 - 然后它会错误地认为你输入了输入。

If the Scanner didn't wait for you to enter another - then it would erroneously assume that you were done typing input.

我的意思是，扫描仪必须等待您输入 - 因为它无法知道下一个输入的长度。

What I mean is, the Scanner must wait for you to enter a - because it has no way to know the length of the next input.

因此，如果用户想要输入 AB -CDE 你停下来在 C 喝了一口咖啡，它得不到正确的输入。 （你期望 [A，B，CDE] 但它会得到 [A，B，C] ）

So, if a user wanted to type A-B-CDE and you stopped to take a sip of coffee at C, it woud not get the correct input. (You expect [ A, B, CDE ] but it would get [ A, B, C ])

当你以完整的字符串传递它时，扫描器知道输入的结尾是，并且不需要等待另一个分隔符。

When you pass it in a full String, Scanner knows where the end of the input is, and doesn't need to wait for another delimiter.

我将如何做到：

Scanner stdin = new Scanner(System.in);
String input = stdin.nextLine();
String[] splitInput = input.split("-", -1);

现在你将有一个数组的数组包含所有 - 之间的数据。

You will now have an array of Strings that contain the data between all of the -s.

这是<$的链接c $ c> String.split（）您的阅读乐趣文档。

Here is a link to the String.split() documentation for your reading pleasure.

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