java：在字符串中找到一个单词，如果在特定位置用新单词替换

Question

I have a sample string such as :

" I Love cricket. I Love football. I Love tennis. I Love every game!!! "

Now what I want to do is first time replace the the I (at position 1 ) to " We ". So it becomes

" We Love cricket. I Love football. I Love tennis. I Love every game!!! "

Again in the second run I want to replace I (at position 7 ) to " We " .

" I Love cricket. I Love football. We Love tennis. I Love every game!!! "

So what I mean to say is replacing a word at a specific position with a new word. I tried following things so far:

1. ReplaceAll - worked for only when the words are uniques but fails in every other scenario.
2. StringTokenizer - used it go get an arraylist. replaced the word at the spcific position and then again appended all elements in the arraylist. Issue is the special characters are lost.

Please suggest a better way out of doing it.

EDIT: The delimeter can change and isn't specifically a " ".

Answer 1

yourString.split(" ") gives an array of words. Assign new value to the specified index and then append the entries via space(" ") delimiter to produce new resulting string.

public static void main(String args[]) throws Exception 
{
    String testString = " I Love cricket. I Love football. I Love tennis. I Love every game!!! ";
    String[] words = testString.split(" ");
    words[7] = "We";
    String newString = "";

    for (int i = 0; i < words.length; i++)
        newString += " " + words[i];

    System.out.println(newString);
}

Answer 2

StringBuilder sb = 
    new StringBuilder(" I Love cricket. I Love football. I Love tennis. I Love every game!!! ")

sb.replace(1, 2, "We")
  .replace(35, 36, "We")

return sb.toString()

If you need to dynamically find positions of "I" and replace some of them with "We" then it's another story, but you get the idea.

replace(int start, int end, String str): Replaces the characters in a substring of this sequence with characters in the specified String. It returns this so you can chain several replace calls.

Answer 3

改用StringBuilder ，使用insert()方法。

Answer 4

Instead of using replaceAll use straight regex with Pattern . And just replace your first match rather than global. Or just use replaceFirst()