“(?i)” does not work with accents

Question

I have a Java method that looks for a word inside a phrase ignoring the case sensitivity of the word, and if it finds the word then it removes it from the phrase. The word and the phrase can be anything. They're variant. Here is my code :

private String removeWord( String phrase, String word ) {
    phrase = phrase.replaceAll( "(?i)" + word , "" );
    return phrase;
}

Things work perfect, unless the word has an accent. For example if the word is "álvarez" and the phrase is "Álvarez phrase", then it won't work as "(?i)" fails to work in that case.

Is there a way to make "(?i)" work with accented characters ?

Answer 1

Just replace (?i) with (?iu) - it will turn on unicode case-insensitive matching

Answer 2

By default (?i) works only with ASCII characters - see Pattern.CASE_INSENSITIVE for details. You could combine that flag with UNICODE_CASE together like so:

phrase = Pattern.compile(word, UNICODE_CASE | CASE_INSENSITIVE).matcher(phrase).replaceAll("");