我如何分隔字符串，以便“ cat！”将变为“ cat！”

Question

I believe this program will work for most instances except one. I added spaces in indexOF() so words like cathrine and dogsuit lammas Would all be accepted as non profane. The only problem i see is if the user starts the line with cat/dog/llama. CAT! Would show up as non profane because there is no space at the start and there is no space afterwards, is there a String command to spread things out or am i completely on the wrong path?

import java.util.Scanner;
public class ProfanityFilter 
{

 public static void main(String[] args) 
 {

   System.out.println (" welcome to the Profanity filter billboard service ");
   System.out.println (" please enter  a potential sign that contains the words \"cat\", \"dog\" or \"llama\"" );

   Scanner keyboard = new Scanner (System.in);

   String s1 = keyboard.nextLine();

   s1 = s1.toLowerCase();

   if (s1.indexOf(" cat ")!=-1 || s1.indexOf(" dog ") !=-1 || s1.indexOf(" llama ")!=-1)

         System.out.println ("Profanity is in your Billboard");
   else
        System.out.println ("There is no profanity in your Billboard");

 }
}

Answer 1

Regex to the rescue!

if (s1.matches("^.*\\b(cat|dog|llama)\\b.*$"))

Some explanation:

• \\b means word boundary
• (a|b|c) means "a or b or c"

You could construct this from an array:

String[] badWords = {"cat", "dog", "llama"};
String regex = "^.*\\b(" + 
    Arrays.toString(badWords).replace(", ", "|").replace("[", "").replace("]", "") + 
    ")\\b.*$";

Answer 2

看一下Pattern类和\\b ，这意味着单词边界。

Answer 3

您应该使用正则表达式 。

Answer 4

You could do as follows that way it will work for "cat" and "horse, cat, and goat" as well.

if(Regex.IsMatch(s1, @"\b(?:cat|dog|llama)\b", RegexOptions.IgnoreCase))
    System.out.println("Profanity is in your Billboard");

Okay, I thought it was C#, but something similar exists in Java.