使用NSCharacterSet删除所有不需要的字符

Question

我想从NSString中删除所有不是的字符(数字、字母、来号、空格或句号)。

我正在使用NSCharacterSet，但它没有添加内容的方法。我尝试在可变版本中添加空格、逗号和句号，但没有成功。

 // str is my string
 NSCharacterSet *charactersToRemove =
 [[ NSCharacterSet letterCharacterSet ] invertedSet ];

 NSString *trimmedReplacement =
 [[ str componentsSeparatedByCharactersInSet:charactersToRemove ]
 componentsJoinedByString:@"" ];
 // this removes spaces, periods, and commas too. How do I add in to the character set to keep them

Answer 1

创建可变字符集，并添加要保留的其他字符。此外，如果您还想在字符串中保留数字，那么您可能打算使用alphanumericCharacter set而不是letterCharacterSet。

NSMutableCharacterSet *charactersToKeep = [NSMutableCharacterSet alphanumericCharacterSet];
[charactersToKeep addCharactersInString:@" ,."];

NSCharacterSet *charactersToRemove = [charactersToKeep invertedSet];

NSString *trimmedReplacement = [[ str componentsSeparatedByCharactersInSet:charactersToRemove] componentsJoinedByString:@"" ];