NSPredicate

如何比對user輸入的字串，讓他符合我限定的！？

可以用這個例子：

-(BOOL) textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string

{

   

    if (textField == self.sideFirstPassField) {

        NSString *resultString = [textField.text stringByReplacingCharactersInRange:range withString:string];

        NSString *strictString = @"[a-zA-Z0-9]*";

        BOOL predicate = [[NSPredicate predicateWithFormat:@"SELF MATCHES%@",strictString] evaluateWithObject:resultString];

        return predicate;

    }

    return YES;

}