为什么我的string.length减0，如果我拆分此字符串？ [英] why is my string.length 0 if I split this string?

问题描述

这可能是一个非常简单的问题，但我会先给你code。

This is probably a very easy question but I'm going to give you the code first.

import java.util.Scanner;

public class help {
public static void main(String args[]) {
    Scanner sc = new Scanner(System.in);

    System.out.print("Give: ");
    String s = sc.next();

    String[] parts = s.split(".");

    System.out.println(parts.length);
}
}

就算我给192.168.1.1.1.1.1或1.2.3或...的parts.length将始终为0，可以有人请向我解释为什么，我该如何让它4，如果我进入1.2 .3.4？

Even if I give 192.168.1.1.1.1.1 or 1.2.3 or ... the parts.length will always be 0, can somebody please explain to me why and how I can let it be 4 if i enter 1.2.3.4?

推荐答案

您需要 s.split（\\\\）因为参数拆分是一个普通的前pression。在。字符在常规的前pression意味着任何字符，你需要用反斜杠来逃避它有它的意思是点。

You need s.split("\\.") because the argument to split is a regular expression. The . character in a regular expression means "any character", and you need to escape it with the backslash to have it mean "dot".

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