Can someone help me with writing a regular expression?

Question

I'm making a search function for my app and I need a good regular expression. Right now, when the user searches "RAC" (it's a band name), it returns all of my posts that have the letters "rac" in the title. This, however, is a bit broken and can only be fixed by a regular expression. I will provide some examples and say whether or not they should be included.

1. Sir Sly - Miracle : DON'T INCLUDE
2. RAC - Let Go : INCLUDE
3. Amtrac - Walkin' : DON'T INCLUDE
4. Bastille - Laura Palmer (RAC Remix) : INCLUDE
5. Cold War Kids - Miracle Mile : DON'T INCLUDE
6. MNDR - Feed Me Diamons (ft. RAC) : INCLUDE

Does anyone have a good regular expression that could help me out? PS you can test your regular expression here .

Answer 1

Edit: this is a solution for Java - if not the intended language, please refine your tags

You can use word boundaries for this, and a case-sensitive Pattern , as such:

String[] inputs = {"Sir Sly - Miracle",// : DON'T INCLUDE
        "RAC - Let Go",// : INCLUDE
        "Amtrac - Walkin'",// : DON'T INCLUDE
        "Bastille - Laura Palmer (RAC Remix)",// : INCLUDE
        "Cold War Kids - Miracle Mile",// : DON'T INCLUDE
        "MNDR - Feed Me Diamons (ft. RAC)"// : INCLUDE
        };
Pattern p = Pattern.compile("\\bRAC\\b");
for (String input: inputs) {
    Matcher m = p.matcher(input);
    System.out.printf("%s --> found ? %b%n", input, m.find());
}

Output

Sir Sly - Miracle --> found ? false
RAC - Let Go --> found ? true
Amtrac - Walkin' --> found ? false
Bastille - Laura Palmer (RAC Remix) --> found ? true
Cold War Kids - Miracle Mile --> found ? false
MNDR - Feed Me Diamons (ft. RAC) --> found ? true

Answer 2

There's many tools that can help you instead of rolling your own solution. Have you considered Lucene

Answer 3

Similar solution... but more efficient
in order to avoid to allocate useless objects

String[] bands =  {"Sir Sly - Miracle",// : DON'T INCLUDE
                   "RAC - Let Go",// : INCLUDE
                   "Amtrac - Walkin'",// : DON'T INCLUDE
                   "Bastille - Laura Palmer (RAC Remix)",// : INCLUDE
                   "Cold War Kids - Miracle Mile",// : DON'T INCLUDE
                   "MNDR - Feed Me Diamons (ft. RAC)",// : INCLUDE
};

for(String s : bands){
    if(Pattern.matches(".*(RAC).*", s))
            System.out.printf("%s\n",s);
}