Replace string for exact match with conditions

Question

Sample string

astabD (tabD) tabD .tabD tabD. (tabD tabD)

I need to replace tabD with something like temp.tabD for every of the occurrence in the above string except the first and second one.

For this I tried replaceAll with word boundary

str.replaceAll("\\b"+ "tabD" + "\\b"," temp.tabD "))

Works except for the second occurrence. Would appreciate any help since '(' and ')' are also keywords and only the occurrence of both have to be ignored.

Answer 1

You may use

.replaceAll("\\b(?<!\\((?=\\w+\\)))tabD\\b", "")

Or, if tabD comes in from user input:

String s = "astabD (tabD) tabD .tabD tabD. (tabD tabD)";
String word = "tabD";
String wordRx = Pattern.quote(word);
s = s.replaceAll("(?<!\\w)(?<!\\((?=" + wordRx + "\\)))" + wordRx + "(?!\\w)", "");

See the regex demo .

Details

• \\b - a word boundary ( (?<!\\w) is an unambiguous left word boundary)
• (?<!\\((?=\\w+\\))) - a negative lookbehind that fails the match if right before the current location there is a ( that is followed with 1+ word chars ( \\w+ is required to match the tabD word) followed with ) ( NOTE : If your IDE tells you the + is inside a lookbehind, it is the IDE bug since the + is in a lookahead here and + / * quantifiers are allowed in lookaheads)
• tabD - the word to find
• \\b - a word boundary ( (?!\\w) is an unambiguous right word boundary)

Java demo :

String s = "astabD (tabD) tabD .tabD tabD. (tabD tabD)";
System.out.println(s.replaceAll("\\b(?<!\\((?=\\w+\\)))tabD\\b", ""));
// => astabD (tabD)  . . ( )