Split string with dot as delimiter

Question

I am wondering if I am going about splitting a string on a . the right way? My code is:

String[] fn = filename.split(\".\");
return fn[0];
         


        

Answer 1

the String#split(String) method uses regular expressions. In regular expressions, the "." character means "any character". You can avoid this behavior by either escaping the "."

filename.split("\\.");

or telling the split method to split at at a character class:

filename.split("[.]");

Character classes are collections of characters. You could write

filename.split("[-.;ld7]");

and filename would be split at every "-", ".", ";", "l", "d" or "7". Inside character classes, the "." is not a special character ("metacharacter").