Question

Being a Java Newbie, I am struggling with String.split. Trying to tokenism the following string

"(3,3,{S,W,P},{P,W,P},{P,P,P}),(1,2,{S,E}),(2,1,{{S},{E}})"

with the regex pattern "\\{|\\(|\\}|\\)|\\s|," using String.split.

Unfortunately, it also returns empty Strings where ever match occurs which I want to suppress similar to what StringSplitOptions.RemoveEmptyEntries does in C#.

On the contrary using StringTokenizer works quite well, but being deprecated I am trying to avoid it. To make my question clear I am trying an equivalent behavior with String.split as I would get using the following Tokenizer

new StringTokenizer(input2, "{},() \t")

Please suggest, how should I proceed.

Answer 1

First, you can eliminate most of those backslashes by using a character class instead of alternation. Then, as Christopher said, you can add a + to mimic StringTokenizer’s behavior of matching one or more delimiter characters:

"[{},()\\s]+"

Unfortunately, there’s no way to prevent that first, empty token when the string starts with a delimiter. Trailing empty tokens are automatically dropped, but you have to filter out the leading one yourself.

Of course, you’re free to use StringTokenizer if you want, or a third-party tool like Guava’s Splitter.