Replacing nth occurrence of word with a replacement word in Java

问题

I am doing homework related to Java language. I am reading a text file from a website via socket with:

BufferedReader br = new BufferedReader(inr);

while((line2 = br.readLine()) != null)
{...}

I need to replace the nth occurrence of the target word with a replacement word only if n is odd. For example:

line2 is readed as "ces11111111". target word is 11 ; replacement word is CS219. Thus , result line is cesCS21911CS21911.

How can I achieve this ? Please help me to complete my homework.

回答1:

Here is my code:

public static String replaceIfOdd(String stringToChange,
        String searchingWord, String replacingWord) {
    final String separator = "#######";
    String splittingString = stringToChange.replaceAll(searchingWord,
            separator + searchingWord);
    String[] splitArray = splittingString.split(separator);
    String result = "";
    for (int i = 0; i < splitArray.length; i++) {
        if (i % 2 == 1)
            splitArray[i] = splitArray[i].replace(searchingWord,
                    replacingWord);
        result += splitArray[i];
    }
    System.out.println(result);
    return result;
}

Way to call it:

replaceIfOdd("ces11111111", "11", "CS219");

The logic behind this is the following:

I replace all the occurrences of the searchingWord with separator + searchingWord. After that I just split the resulting string using the split function. Then I loop through all the elements of the array and I make the right replacement only when the searchingWord appears in an odd position into the array and, at the same time, I just recreate the string with the right replacements done.

Hope this is what you were searching for!

P.S.: I used a string separator in order to break down the stringToChange, obviously if into your stringToChange there was such a string, the method wouldn't give you the right result ... I will try to think about a different implementation if you are worried about it. Ciao!

回答2:

    String in = "ces11ccc11ceb11";
    in = "ces11111111";
    String target = "11";
    String replacement = "CS219";
    int j=0;
    boolean flag=true;
    String result = "";

    for(int i=0;i<in.length();i++)
    {

        if(in.length()-i<target.length()) break;
        if(in.charAt(i)==target.charAt(0))
        {
            if(in.substring(i, i+target.length()).equals(target))
            {
                if(flag)
                {   
                    result += replacement;
                }
                else result += target;
                flag=!flag; 
                i = i+target.length()-1;
            }
            else result += in.charAt(i);

        }
        else
        {
            result += in.charAt(i);
        }

    }

    System.out.println(result);

来源：https://stackoverflow.com/questions/19856042/replacing-nth-occurrence-of-word-with-a-replacement-word-in-java