使用NSCharacterSet刪除所有不需要的字符

Question

我想從我的NSString中刪除不是（數字，字母，來，空格或句點）的所有字符。

我正在使用NSCharacterSet，但它沒有添加到它的方法。我嘗試使用可變版本添加空格，逗號和句點，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

創建一個可變字符集並添加要保留的其他字符。如果你想讓字符串中的數字也可以用字母數字字符集代替letterCharacterSet。

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

NSCharacterSet *charactersToRemove = [charactersToKeep invertedSet]; 

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