Question

I am trying to write a simple Java function that will take a list of Language Inputs and see if what I obtained from a database query matches. All of the strings in my database have been normalized to make searches easier. Here is an example.

Research Lab A wants participants that have any of the following language inputs (they are separated by the pipe character | ):

{English | English, Spanish | Spanish} 

In other words, this lab can take participants that are either monolingual English, monolingual Spanish, or bilingual English and Spanish. This is very straightforward – if they database result returns "English" or "English, Spanish" or "Spanish", my function will find a match.

HOWEVER, my database also marks if a participant only has minimal language input for some language (using the ~ character).

"English, ~Spanish" = participant hears English and a little Spanish
"English, ~Spanish, Russian" = participant hears English, Russian, and a little Spanish

This is where I am having trouble. I want to match something like "English, ~Spanish" with both "English" and "English, Spanish".

I was thinking of just remove/hiding the languages with a marked ~, but if there is a research lab that wants only {English, Spanish}, then "English, ~Spanish" will not match, even though it should.

I also cannot think of how I could use regular expressions to do this task. Any help will be greatly appreciated!

Answer 1

Try this

\b(English[, ~]+Spanish|Spanish|English)\b

Code

try {
    if (subjectString.matches("(?im)\\b(English[, ~]+Spanish|Spanish|English)\\b")) {
        // String matched entirely
    } else {
        // Match attempt failed
    } 
} catch (PatternSyntaxException ex) {
    // Syntax error in the regular expression
}

Explanation

"\\b" +               // Assert position at a word boundary
"(" +                // Match the regular expression below and capture its match into backreference number 1
                        // Match either the regular expression below (attempting the next alternative only if this one fails)
      "English" +          // Match the characters “English” literally
      "[, ~]" +            // Match a single character present in the list “, ~”
         "+" +                // Between one and unlimited times, as many times as possible, giving back as needed (greedy)
      "Spanish" +          // Match the characters “Spanish” literally
   "|" +                // Or match regular expression number 2 below (attempting the next alternative only if this one fails)
      "Spanish" +          // Match the characters “Spanish” literally
   "|" +                // Or match regular expression number 3 below (the entire group fails if this one fails to match)
      "English" +          // Match the characters “English” literally
")" +
"\\b"                 // Assert position at a word boundary

UPDATE

A more generalized form would be something like this:

(?-i)\b([A-Z][a-z]+[, ~]+[a-z]+|[A-Z][a-z]+)\b

BTW, doing so you might be messed up, as this pattern would going to match a all Capitalized word. There might be a better option to do so by using this syntax while generating your RegEx pattern.

(A[, ~]+B|A|B)

Where A, B would be name of languages. I think this would be a better approach.