Try this, it may work
-(NSString *) formatIdentificationNumber:(NSString *)string
{
NSCharacterSet * invalidNumberSet = [NSCharacterSet characterSetWithCharactersInString:@"\n_!@#$%^&*()[]{}'\".,<>:;|\\/?+=\t~` "];
NSString * result = @"";
NSScanner * scanner = [NSScanner scannerWithString:string];
NSString * scannerResult;
[scanner setCharactersToBeSkipped:nil];
while (![scanner isAtEnd])
{
if([scanner scanUpToCharactersFromSet:invalidNumberSet intoString:&scannerResult])
{
result = [result stringByAppendingString:scannerResult];
}
else
{
if(![scanner isAtEnd])
{
[scanner setScanLocation:[scanner scanLocation]+1];
}
}
}
return result;
}
or see the link