Is there a way to replace all char with @ between two given patterns in java

Question

I have a string something like this

Hello #'World'# , currently i am in #'world's'# best location.

I need to replace this all the chars between #' and '# using regex in java i need a final string should be in this format

Hello #'@@@@@'# , currently i am in #'@@@@@@@'# best location.

possible duplicate of [Learning Regular Expressions](http://stackoverflow.com/questions/4736/learning-regular-expressions) — Andy Brown, Sep 07 '15 at 07:34
@AndyBrown, well, the replacement depends on the (length of the) match, so it's not a simple call to `replaceAll`. — aioobe, Sep 07 '15 at 07:38
Do you mean it must use `replaceAll()`, or is it ok to just use regex to find string to replace? Does it absolutely have to be regex? — Andreas, Sep 07 '15 at 07:49

score 1 · Answer 1 · answered Sep 07 '15 at 08:00

Solution not using regex:

String input = "Hello #'World'# , currently i am in #'world's'# best location.";

StringBuilder buf = new StringBuilder(input.length());
int start = 0, idx1, idx2;
while ((idx1 = input.indexOf("#'", start)) != -1) {
    idx1 += 2;
    if ((idx2 = input.indexOf("'#", idx1)) == -1)
        break;
    buf.append(input, start, idx1); // append text up to and incl. "#'"
    for (; idx1 < idx2; idx1++)
        buf.append('@'); // append replacement characters
    start = idx2 + 2;
    buf.append(input, idx2, start); // append "'#"
}
buf.append(input, start, input.length()); // append text after last "'#"
String output = buf.toString();

System.out.println(input);
System.out.println(output);

Output

Hello #'World'# , currently i am in #'world's'# best location.
Hello #'@@@@@'# , currently i am in #'@@@@@@@'# best location.

Is there a way to replace all char with @ between two given patterns in java

1 Answers1