My Point of View – Page 69 – Source, Ingest, Prepare, Analyze and Consume

Excel dropdown list with number and text

There are two methods;

Data validation drop down

There is a list option in Data validation. If this is combined with a VLOOKUP formula you would be able to convert the selected value into a number.

The steps in Excel 2010/2019 are:

Create your list with matching values.
On the Data tab choose Data Validation
The Data validation form will be displayed
Set the Allow dropdown to List
Set the Source range to the first part of your list
Click on OK (User messages can be added if required)

In a cell enter a formula like this

=VLOOKUP(A5,$E$5:$F$8,2,FALSE)

which will return the matching value from the second part of your list.

Form control drop down

Alternatively, Form controls can be placed on a worksheet. They can be linked to a range and return the position number of the selected value to a specific cell.

If you don’t see Developer tab in Excel ribbon, follow this link;

Show the Developer Tab

The steps in Excel 2010/2019 are:

Create your list of data in a worksheet
Click on the Developer tab and dropdown on the Insert option
In the Form section choose Combo box or List box
Use the mouse to draw the box on the worksheet
Right click on the box and select Format control
The Format control form will be displayed
Click on the Control tab
Set the Input range to your list of data
Set the Cell link range to the cell where you want the number of the selected item to appear
Click on OK

Server is ethernet connected on LAN, means exposed to the internet?

You may have an Internet connection, but you are almost certainly behind a NAT router, not directly connected to the Internet. Normally, that NAT router is the only machine that faces the Internet, has a direct connection, and is under constant attack by numerous bots roaming the IP’s of the Internet.

You only have a local IP for your local network. Only the router has your true IP that is seen on the Internet. When your browser or NTP service (or other Internet need you may have) needs to see something on the Internet, it makes a connection to an Internet server, and your router notes that connection and allows that server to respond, using the associated ports of your connection. The router will route those responses back to your machine, and not any other.

The outside bots and servers cannot attack or connect to your machine, because they can’t even see it, and they don’t know your local IP. The only contact that outside machines can have with your machine is strictly through connections your machine initiates first, through your router.

Now if you *did* want to put your server directly on the Internet, most routers have a setting where they can put any machine into a ‘DMZ’, a special unprotected zone, which means the Internet is directly connected to any machine you choose! And the router won’t block any Internet traffic then, but allow all of it to come through to you.

I would strongly advise you to first disconnect ALL of your drives, and backup your boot drive, because you will be very rapidly attacked! Never use the DMZ unless you have a lot of security experience!

IEnumerable vs IQueryable

The IEnumerable and IQueryable are used to hold a collection of data and also used to perform data manipulation operations such as filtering, Ordering, Grouping, etc.

The main difference is this;

We can use SQL Profiler to confirm this behavior.

All about LINQ operators

A short list of LINQ operators.

Using IN clause

This is similar to database IN keyword;

var myInClause = new string[] {"One", "Two", "Three"};

var results = from x in MyTable
              where myInClause.Contains(x.SomeColumn)
              select x;
// OR
var results = MyTable.Where(x => myInClause.Contains(x.SomeColumn));

Using ALL operator

Working with simple types

//does all numbers are greater than 10
int[] IntArray = { 11, 22, 33, 44, 55 };
var Result = IntArray.All(x => x > 10);
Console.WriteLine("Is All Numbers are greater than 10 : " + Result);

//does all names has characters greater than three
string[] stringArray = { "Khan", "Ali", "Adam", "Eve", "Joe" };
Result = stringArray.All(name => name.Length > 3);
Console.WriteLine("Is All Names are greater than 3 Characters : " + Result);

var letterResult = stringArray.All(name => name.StartsWith("A"));
Console.WriteLine("Is All Names start with letter A : " + letterResult);

//all numbers can be divided by three
int[] numbers = { 3, 6, 9, 12};
bool iSNumbersDivided = numbers.All(number => number % 3 == 0);
Console.WriteLine($"Numbers are divisible by three = {iSNumbersDivided}");

Working with complex types

//Check whether age of all animals in the zoo is greater than 1 year
bool response = animalData.All(x => x.AnimalAge > 1);
Console.WriteLine($"Is All Animals are greater than 1 years old : {response}");

//get all animas who are feed by milk
var zooSubSet = animalData.Where(x => x.Food.All(y => y.FoodType == "Milk"));
foreach(var item in zooSubSet)
{
    Console.WriteLine($"Animal Name: {item.AnimalName}");
}

Resources

https://stackoverflow.com/questions/959752/where-in-clause-in-linq

https://coderedirect.com/questions/644629/linq-nested-list-contains

Handling custom dataset in C#

I am receiving this dataset from a remote server;

TagNumber	TagCode	CageNumber	FoodType	FoodValue
A-2021-1	WHITE	A9:I10	        Milk	        A11:I
A-2021-1	WHITE	A9:I10	        Corn	        A10:I
A-2021-1	RED	A11:I13	        Meat	        B1:B2
A-2021-1	RED	A11:I13	        Hay	        A14:I
A-2021-1	GREEN	A8:J9	        Milk	        B1:B2
A-2021-1	GREEN	A8:J9	        Milk	        A10:J

I need to create this object, a complex type;

public class Animal
{
    public string TagNumber { get; set; }
    public string TagCode { get; set; }
    public string CageNumber { get; set; }
    public List<AnimalFood> Food { get; set; }
}

public class AnimalFood
{
    public string FoodType { get; set; }
    public string FoodValue { get; set; }
}

There could be many ways to handle this. This is one of them;

Create a dictionary object using LINQ GroupBy and TagCode column from incoming dataset;

var allAnimals = animalData
    .GroupBy(item => item.TagCode)
    .ToDictionary(grp => grp.Key, grp => grp.ToList());

Create unique animals out of dictionary object;

var uniqueAnimals = allAnimals.Keys.Distinct().ToList();

Create the object (animal) and add them to zoo :);

var zoo = new List<Animal>();
foreach (string animal in uniqueAnimals)
{
    var animalRow = allAnimals[animal];
    var animalRowFirst = animalRow.FirstOrDefault();
    var animalRecord = new Animal
    {
         TagNumber = animalRowFirst.TagNumber,
         TagCode = animalRowFirst.TagCode,
         CageNumber = animalRowFirst.CageNumber
    };
    //time for food
    var animalFood = new List<AnimalFood>();
    foreach(var item in animalRow)
    {
        item.Food.ForEach(x =>
        {
            animalFood.Add(new AnimalFood
            {
                  FoodType = x.FoodType,
                  FoodValue = x.FoodValue
            });
        });
    }
   //this is our custom type
   animalRecord.Food = animalFood;
   zoo.Add(animalRecord);
}

Sample output;

It’s easier to apply different filters on this object;

var animalFilter = zoo.Where(x => x.TagCode.ToUpper() == "WHITE");

Resources

https://stackoverflow.com/questions/3186818/unique-list-of-items-using-linq