String with format, avoiding "(null)" "<null>" and extra spaces, drop this method in your NSString category

NSString+extra.m

// Returns a string with the given format, any nil-values will be eliminated and extra white-space is trimmed away for you =)
+ (instancetype)safeStringWithFormat:(NSString *)format, ...
{
    va_list ap;
    va_start(ap, format);
    NSString *intermediateString = [[NSString alloc] initWithFormat:format arguments:ap];
    va_end(ap);
    
    NSString *resultString = [intermediateString stringByReplacingOccurrencesOfString:@"(null)" withString:@""];
    resultString = [resultString stringByReplacingOccurrencesOfString:@"<null>" withString:@""];
    NSString *squashed = [resultString stringByReplacingOccurrencesOfString:@"[ ]+"
                                                             withString:@" "
                                                                options:NSRegularExpressionSearch
                                                                  range:NSMakeRange(0, resultString.length)];
    
    return [squashed stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
    
}