目标C中的正则表达式替换问题

Question

试图将所有标记大写，并在替换方面遇到麻烦。知道为什么"upperCaseString“方法不起作用吗？

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);

产生:当我期望<kaboom>stuff</kaboom>时<KABOOM>stuff</KABOOM>

Answer 1

stringByReplacingMatchesInString:options:range:withTemplate:不是那样工作的，最后一个参数的类型是NSString，您要传递的字符串是表达式@"$1".uppercaseString - which‘s @"$1"的结果。

一种可能的算法(伪码)：

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