使用NSCharacterSet删除所有不需要的字符

Question

我想从我的NSString中删除不是（数字，字母，来，空格或句点）的所有字符。

我正在使用NSCharacterSet，但它没有添加到它的方法。我尝试使用可变版本添加空格，逗号和句点，但尚未成功。

// 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要保留的其他字符。如果你想让字符串中的数字也可以用字母数字字符集代替letterCharacterSet。

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

NSCharacterSet *charactersToRemove = [charactersToKeep invertedSet]; 

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