CODEWITHSUNDEEP
objective-cregex
Jeffery Jones
Jeffery Jones

Reputation: 75

Regular expression substitution problem in Objective-C

Trying to capitalize all tags and running into trouble with substitution. Any idea why "upperCaseString" method isn't working?

NSError *error = nil;
NSMutableString *stringToCap = [NSMutableString stringWithString:@"<kaboom>stuff</kaboom>"];
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"(</?[a-zA-Z].*?>)" options:NSRegularExpressionCaseInsensitive error:&error];
NSMutableString *modifiedString = [NSMutableString stringWithString:[regex stringByReplacingMatchesInString:stringToCap options:0 range:NSMakeRange(0, [stringToCap length]) withTemplate:@"$1".uppercaseString]];

NSLog(@"%@", modifiedString);

Produces: <kaboom>stuff</kaboom> when I expect <KABOOM>stuff</KABOOM>

Upvotes: 1

Views: 51

Answers (1)

CRD
CRD

Reputation: 53000

stringByReplacingMatchesInString:options:range:withTemplate: doesn't work like that, the type of the last argument is just NSString and the string you are passing is the result of the expression @"$1".uppercaseString – which is just @"$1".

A possible algorithm (pseudo code):

for NSTextCheckingResult *match in [regex matchesInString:... options:... range:...] do
   extract the substring at match.range from modified string
   uppercase it
   replace the substring at match.range with uppercased result

Upvotes: 1

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