How is this regex splitting this string?

Question

I'm having a problem unraveling some Java code sent me. How is this regular expression splitting out the strings with the array?

String[] words = haystack.split("[ \"\'\t\n\b\f\r]", 0);

Answer 1

It is splitting on any of the following in the character class denoted by the opening [ and closing ] :

• – space
• \\" – quote
• \\' – apostrophe
• \\t – tab
• \\n – line feed
• \\b – backspace
• \\f – form feed
• \\r – carriage return

See the Java regex reference for clarification about regex character classes and characters.

Also, note that \\' could very well be ' , escaping being unnecessary in that case. Check out an example split on Ideone with this little change.

Answer 2

I think you mean haystring (which is a string) is split into an array of strings. All white space characters are used as a delimeter.