Question

I never understood how to make properly regex to divide my Strings.
I have this types of Strings example = "on[?a, ?b, ?c]";
Sometimes I have this, Strings example2 = "not clear[?c]";

For the first Example I would like to divide into this:

[on, a, b, c] 

or

String name = "on";
String [] vars = [a,b,c];

And for the second example I would like to divide into this type:
[not clear, c]
or

String name = "not clear";
String [] vars = [c];

Thanks alot in advance guys 😉

Answer 1

If you know the character set of your identifiers, you can simply do a split on all of the text that isn’t in that set. For example, if your identifiers only consist of word characters ([a-zA-Z_0-9]) you can use:

String[] parts = "on[?a, ?b, ?c]".split("[\\W]+");
String name = parts[0];
String[] vars = Arrays.copyOfRange(parts, 1, parts.length);

If your identifiers only have A-Z (upper and lower) you could replace \\W above with ^A-Za-z.

I feel that this is more elegant than using a complex regular expression.

Edit: I realize that this will have issues with your second example “not clear”. If you have no option of using something like an underscore instead of a space there, you could do one split on [? (or substring) to get the “name”, and another split on the remainder, like so:

String s = "not clear[?a, ?b, ?c]";
String[] parts = s.split("\\[\\?"); //need the '?' so we don't get an extra empty array element in the next split
String name = parts[0];
String[] vars = parts[1].split("[\\W]+");