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，来，空格或句点）的字符。

我正在使用NSCharacterSet，但它无法添加到它。我尝试了可变版本添加空格，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

创建一个可变字符集并添加您想要保留的其他字符。如果你想在字符串中保留数字，你可能也意味着使用字母数字字符集而不是letterCharacterSet。

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

NSCharacterSet *charactersToRemove = [charactersToKeep invertedSet];

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