objective-c - 使用 NSCharacterSet 删除所有不需要的字符

Question

我想从我的 NSString 中删除所有不是(数字、字母、come、空格或句点)的字符。

我正在使用 NSCharacterSet，但它没有添加方法。我尝试了可变版本来添加空格、逗号和句点，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。如果您也想在字符串中保留数字，您可能还想使用 alphanumericCharacter set 而不是 letterCharacterSet。

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

NSCharacterSet *charactersToRemove = [charactersToKeep invertedSet];

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