I have a number of NSStrings of movie titles like this:
@"Accepted (2006)"
@"Blade Runner (1982)"
@"(500) Days of Summer (2009)"
@"RoboCop (1987) - Criterion #23"
I am trying to get the four-digit numeric-only year that is always between ( and ) out of the title.
Whats the proper way to do this? NSRange? RegEx? Something else? Objective-C please, not Swift.
Use a lookaround based regex.
"(?<=\\()\\d{4}(?=\\))"
or
Use capturing group.
"\\((\\d{4})\\)"
Since (, ) are regex meta-characters, you need to escape those in-order to match the literal ( or ) symbols.
ie
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"\\((\\d{4})\\)" options:0 error:NULL];
NSString *str = @"Accepted (2006)";
NSTextCheckingResult *match = [regex firstMatchInString:str options:0 range:NSMakeRange(0, [str length])];
For this it is simpler to use the NSString method: rangeOfString:options: with the option NSRegularExpressionSearch with a look-behind and look-ahead based regex:
NSRange range = [test rangeOfString:@"(?<=\\()\\d{4}(?=\\))" options:NSRegularExpressionSearch];
NSString *found = [test substringWithRange:range];
NSLog(@"found: %@", found);
Output:
found: 2006
For more information see the ICU User Guide: Regular Expressions
