括号内容的正则表达式

Question

I'm trying to learn Regular Expressions but I can't understand how to set this one up correctly as an NSRegularExpression. I need to get the contents of any parentheses in a string.

So: Belmont (O'Hare Branch) (Forest Pk-bound)

would give me: 'O'Hare Branch' and 'Forest Pk-bound'

I would really appreciate a commented example.

Thank you!

Answer 1

\\(.*?\\) will give you everything in between brackets. Sorry but I have no clue how to do it in a NSRegularExpression. You either have to wait for a IOS dev to come along or figure it our for yourself.

\( #escaped opening bracket
  . #match anything
  * #match . 0 - unlimited times
  ? #make the * not greedy
\) #escaped closing bracket

Answer 2

@"\\(.*?\\)"

Will do the work.

Notice: That won't support nested parentheses like this:

Hi duck (debug duck (now just a regular duck))

So, the whole solution will be:

NSString *string = @"Hi duck (debug duck), let's go to shower!";
NSRange range = NSMakeRange(0, [string length]);
NSString *pattern = @"\\(.*?\\)";
NSError  *error = nil;

NSRegularExpression* regex = [NSRegularExpression regularExpressionWithPattern:pattern options:0 error:&error];
NSTextCheckingResult *match = [regex firstMatchInString:string options:0 range:range]; 

NSLog(@"%@", [string substringWithRange:[match rangeAtIndex:0]]);