有条件结束正则表达式

Question

I am looking for a regex to split a string containing ().

This is what I have

String regex = "(?=\\()|()"

The first part is correct so that it starts with the "(". I need the second part to end on the ")", but if there is a number after the ")" it need to end on the number.

example Fe2(CH3)2(CH2O)(CH3)

This needs to split into

Fe2

(CH3)2

(CH2O)

(CH3)

The number after the ")" can be either a single or double digit.

I also needs to split Fe(C5H5)2O4(CH3) for example into

Fe

(C5H5)2

O4

(CH3)

Answer 1

Updated, the new logic: match either some letter chars or something parenthesized, followed by optional digits.

final String f = "Fe2(CH3)2O4(CH2O)2(CH3)";
final Matcher m = Pattern.compile("(\\p{L}+|\\(.*?\\))\\d*").matcher(f);
while (m.find()) System.out.println(m.group());

Answer 2

Edit

Hope this works for you :)

String s="Fe2(CH3)2(CH2O)(CH3)23O4(CH3)";
String[] array=s.split("(?=\\()|(?<=\\)[0-9]{1,2}+)");
System.out.println(Arrays.toString(array));
//out: [Fe2, (CH3)2, (CH2O), (CH3)23, O4, (CH3)]

Answer 3

I don't know about java-regex specific things but this worked for me in .net:
(^[A-Za-z0-9]+)|(\\([A-Za-z0-9]+\\)[A-Za-z0-9]{0,2})
(unescaped, put additional \\ where needed...)

EDIT: now I have read about the stuff you're doing. My regex WON'T work for SPLITTING, rather you should call match on it. And every match will be one piece for you.

And if this doesn't exactly do what you want, please specify more inputs and desired outputs (especially ones that this one doesn't cover), and I'm more than happy to help...

Answer 4

Looks like i found a soln which works for all cases:

Enter your regex: \(.*?\)[0-9]{0,2}|[\w]+
Enter input string to search: Fe2(CH3)2O4(CH2O)(CH3)
I found the text "Fe2" starting at index 0 and ending at index 3.
I found the text "(CH3)2" starting at index 3 and ending at index 9.
I found the text "O4" starting at index 9 and ending at index 11.
I found the text "(CH2O)" starting at index 11 and ending at index 17.
I found the text "(CH3)" starting at index 17 and ending at index 22.

Here is the regex to be used in the code:

String regEx = "\\(.*?\\)[0-9]{0,2}|[\\w]+";

In short it looks for strings starting with '(' and ending with ')' and numbers. If thats not there then it looks for strings like 'Fe2' , 'O4' etc.