Bug in String.split('.')?

Question

I can hardly believe it but split() doesn't work on the . character:

String createDate = '01.2.2013';
String[] cd = createDate.split('.');
System.assertEquals(3, cd.size());   // Boom!

Tried with '\.' but it also doesn't work.

Answer 1

The separator string used in the split method is a regular expression and "." is a special character in regular expressions.

The regular expression for a literal "." is "\."

However "\" is also used to escape characters when expressing Strings in Apex, and so this character too needs escaping:

String[] cd = createDate.split('\\.');

The documentation provides an interesting example, if you need to use "\" as the separator:

List<String> parts = filename.split('\\\\');