Regular expression matching strings where it contains a specific word that has a period

I am trying to write a regular expression that matches string that contain a certain word with a period for example (apple. or grape.). I got it to work without the period but not quite sure how to get it to work when there is a period in the word.

What I tried:

(?i)b(Apple|Grape)b (Working correctly without the period)
(?i)b(Apple.|Grape.)b (Returns no matches)

Sample strings that should work:

1 apple.
1 Apple.
apple. 2
grape. 1
test grape.
grape. test
this is a Apple. test

Sample strings that should not work:

1apple.
1Apple.
apple.2
grape.1
testgrape.
grape.test
longwordApple.test
this is a Apple.test

Answer

You could write the pattern as:

b(Apple|Grape).(?!S)

Explanation

• b A word boundary to prevent a partial word match on the left
• (Apple|Grape) Capture either Apple or Grape
• . Match a dot
• (?!S) Assert a whitespace boundary to the right

Regex demo

In Java with the double escaped backslashes:

String regex = "(?<!\S)(Apple|Grape)\.(?!\S)";