NSString* string; // 结果字符串NSString* string1, string2; //已存在的字符串，需要将string1和string2连接起来//方法1. string = [NSString initWithFormat:@"%@,%@", string1, string2 ];//方法2. string = [string1 stringByAppendingString:string2];//方法3 . string = [string stringByAppendingFormat:@"%@,%@",string1, string2];