Captured group regex NSRegularExpression iOS

Question

I am trying to execute the following regex: ^(\$.)([\d]{1,10})?

The result for the $C14325 string at https://regex101.com is [0-2]:"$C" and [2-7]:"14325".

But, when I the following code is executed using NSRegularExpression, then it returns as single matching item, rather than a group.

Basically, I am trying to group those results and finding a way what result corresponds to which regex.

NSString *regexStr=@"^(\\$.)([\\d]{1,10})?";
NSString *inputStr=@"$C14325";
NSError *regexError;
NSRegularExpression *aRegx=[NSRegularExpression regularExpressionWithPattern:regexStr options:NSRegularExpressionCaseInsensitive error:&regexError];
NSArray *results=[aRegx matchesInString:inputStr options:0 range:NSMakeRange(0, inputStr.length)];

There was answer at Named capture groups with NSRegularExpression , but I think rangeAtIndex will throw exception if its not able to find the value.

Answer 1

You've got the regex part right. All you need to do is iterating matches inside the results:

for (NSTextCheckingResult *match in results) {
    NSRange matchRange = [match range];
    NSRange first = [match rangeAtIndex:1];
    NSRange second = [match rangeAtIndex:2];
    NSLog(@"1:%@ 2:%@.", [NSValue valueWithRange:first], [NSValue valueWithRange:second]);
}

1:NSRange: {0, 2} 2:NSRange: {2, 5}.