Question

package main;
import java.util.Arrays;
import javax.swing.*;

public class TweetTester {

    public static void main(String[] args)
    {
        String tweet= JOptionPane.showInputDialog("Please enter a tweet:\n(Hashtags should be represented as #hashtags and mentions should be represented by @mentions)");
        int length = tweet.length();
        if (length<=140)
        {
            String[] splited = tweet.split("\\b+"); //split on space
            if(Arrays.asList(splited).contains("#"))
            {
                int index = tweet.indexOf("#");
                int count = 0;
                while (index != -1)
                {
                    count++;
                    tweet = tweet.substring(index + 1);
                    index = tweet.indexOf("#");
                }
                System.out.println("No of *#* in the input is : " + count);
            }
            if(Arrays.asList(splited).contains("@"))
            {
                int index = tweet.indexOf("@");
                int count2 = 0;
                while (index != -1)
                {
                    count2++;
                    tweet = tweet.substring(index + 1);
                    index = tweet.indexOf("@");
                }
                System.out.println("No of *@* in the input is : " + count2);
            }
            if(Arrays.asList(splited).contains("http://"))
            {
                int index = tweet.indexOf("http://");
                int count3 = 0;
                while (index != -1)
                {
                    count3++;
                    tweet = tweet.substring(index + 1);
                    index = tweet.indexOf("http://");
                }
                System.out.println("No of *http://* in the input is : " + count3);
            }
            //JOptionPane.showMessageDialog(null, (140 - length)+" Charcters Left\n"+"Tweet:\n"+tweet+"\nLength Correct"+ "number of #:"+count);
        }
        if (length>140 ){
            JOptionPane.showMessageDialog(null,"Excess Characters: "+(length-140));
        }
    }
}

Answer 1

首先，您可能应该使用\\s+ regexp：

String[] splited = tweet.split("\\s+"); //split on space

其次，在每个if（）{...}中，您修改（截断）您的原始推文字符串并丢失一些数据。

例如，当你的推文等于：

String tweet = "one @ two # # three # four";

你的第一个if（）删除了origianl tweet字符串的第一部分：

tweet = tweet.substring(index + 1);

并且在第二个if（）推文中没有任何"@"个字符。

上述推文的结果是：

No of *#* in the input is : 3
No of *@* in the input is : 0

Answer 2

你改变了推文。这是不需要的，因为有一个String.indexOf（String seek，int startPos）。更好的是，不要重复自己：

public static int count(String sentence, String word) {
    int count = 0;
    int oldPos = 0;
    for (;;) {
        int pos = sentence.indexOf(word, oldPos);
        if (pos == -1) {
            break;
        }
        count++;
        oldPos = pos + word.length();
    }
    return count;
}

正则表达式"\\b"用于字边界，对http://有问题。实际上，为什么不简单计数，然后测试计数！= 0。

public static void main(String[] args)
{
    String tweet= JOptionPane.showInputDialog("Please enter a tweet:\n"
        + "(Hashtags should be represented as #hashtags and mentions should be "
        + "represented by @mentions)");
    int length = tweet.length();
    if (length<=140)
    {
         int count = count(tweet, "#");
         if (count > 0) {
             System.out.println("No of *#* in the input is : " + count);
         }
         count = count(tweet, "@");
         if (count > 0) {
             System.out.println("No of *@* in the input is : " + count);
         }
         count = count(tweet, "http://");
         if (count > 0) {
             System.out.println("No of *http://* in the input is : " + count);
         }
    }
    else
    {
         JOptionPane.showMessageDialog(null,"Excess Characters: " + (length-140));
    }

不通过每个if语句

2 个答案: