iphone - 包含允许字符的字符串

Question

是否有一种干净的方法来获取只包含允许字符的字符串？

例如:

NSString* myStr = @"a5&/Öñ33";
NSString* allowedChars = @"abcdefghijklmnopqrstuvwxyz0123456789";
NSString* result = [myStr stringWIthAllowedChrs:allowedChars];

结果现在应该是 @"a533";

Answer 1

这不是最干净的，但您可以使用字符集分隔字符串，然后使用空字符串组合生成的数组。

// Create a character set with every character not in allowedChars
NSCharacterSet *charSet = [[NSCharacterSet characterSetWithCharactersInString:allowedChars] invertedSet];
// Split the original string at any occurrence of those characters
NSArray *splitString = [myStr componentsSeparatedByCharactersInSet:charSet];
// Combine the result into a string
NSString *result = [splitString componentsJoinedByString:@""];