Replace all words in java

Question

I'm using the java replaceAll() method for replace matching words in a string. In my case If this word is next to a comma (,) fullstop (.) or anything else like that, this word is not replacing.

example : and. and, and; and(

This is the code:

body = body.replaceAll("(?i) "+knownWord + " ", replaceWord);

Can anyone please suggest me an regular expression which is capable of identifying all the words in this string?

Answer 1

If you want to match specific knownWord do:

  body = body.replaceAll("(?i)\\b"+knownWord + "\\b", replaceWord);

I think what you were looking for is the \\b (word boundary) it is used to detect where words start/end, so commas or dots should no longer be a problem then.

More detailed example in response to your comment:

 String body = "I'm going to school. ";
 String knownWord = "school";
 String replaceWord = "shop";
 System.out.println(body.replaceAll("(?i)\\b"+knownWord + "\\b", replaceWord));

The above will print out the following:

I'm going to shop.

Answer 2

This does as you specify:

(?<![.,])\b(\w+)\b(?![.,])

Debuggex Demo

It finds (and captures) words as long as they are not next to commas or periods. Just add whatever punctuation marks you like to the character-classes, such as [.,?(].

Here is the regex escaped for a Java string: "(?<![.,])\\b(\\w+)\\b(?![.,])"

As far as ignoring case, just pass the CASE_INSENSITIVE flag to your Pattern object, such as with

Pattern p = Pattern.compile(theAbovePattern, Pattern.CASE_INSENSITIVE);