Question

If I have two strings ..
say

string1="Hello dear c'Lint and dear Bob"

and

string2="dear"

I want to Compare the strings and delete the first occurrence of matching substring ..
the result of the above string pairs is:

Hello c'Lint and dear Bob

This is the code I have written which takes input and returns the matching occurence:

System.out.println("Enter your regex: ");
BufferedReader bufferRead = new BufferedReader(new InputStreamReader(System.in));

String RegEx = bufferRead.readLine();
Pattern pattern = Pattern.compile(RegEx);
System.out.println("Enter input string to search: ");
bufferRead = new BufferedReader(new InputStreamReader(System.in));
Matcher matcher = pattern.matcher(bufferRead.readLine());

boolean found = false;
while (matcher.find()) {
    System.out.println("I found the text:\"" + matcher.group() +
            "\" starting at index \'" +
            matcher.start() + 
            "\' and ending at index \'" + 
            matcher.end() + 
            "\'");
}

Answer 1

You could either use:

string result = string1.replaceFirst(Pattern.quote(string2), "");

Or you could avoid regexes entirely:

int index = string1.indexOf(string2);
if (index == -1)
{
    // Not found. What do you want to do?
}
else
{
    String result = string1.substring(0, index) + 
                    string1.substring(index + string2.length());
}

You can report the region here using index and string2.length() very easily. Of course if you want to be able to match regular expression patterns, you should use them.

EDIT: As noted in another answer, both of these will remove "dear" from "and_dear_Bob" leaving "and__Bob" – with the underscores representing spaces. So you’ll end up with two spaces between words. And it doesn’t force the match to be a whole word, either. It does exactly what you described, but it doesn’t give you the result you apparently want.

Edit:
First choice of code outputs: Hello c'Lint and dear Bob
where Hello and c’Lint have two whitespace character in the middle.
While this code:

string result = string1.replaceFirst(Pattern.quote(string2+" "), ""));

gets rid of additional whitespace character.