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I am newbie to C#. If I created a collection with a number of objects.

Let us say my collection looks like this:

var theGalaxies = new List<Galaxy>
{
        new Galaxy() { Name="Tadpole", MegaLightYears=400, Level=1},
        new Galaxy() { Name="Pinwheel", MegaLightYears=25, Level=1},
        new Galaxy() { Name="Milky Way", MegaLightYears=0, Level=2},
        new Galaxy() { Name="Andromeda", MegaLightYears=3, Level=3}
};

foreach (Galaxy theGalaxy in theGalaxies)
   {
       Console.WriteLine(theGalaxy.Name + "  " + theGalaxy.MegaLightYears);
   }

How can I count how many objects is categorized in respective "level" and print out the information like the following output:

Name   MegaLightYears  Level
Tadpole  400            1
Pinwheel  25            1
2 galaxies in Level 1 
Milky Way  0            2
1 galaxy in Level 2 
Andromeda  3            3
1 galaxy in Level 3

Is there any way to print out information so it reserves a certain space for the input so the output does not look like this:

    Name   MegaLightYears  Level
Tadpole  400   1
Pinwheel  25 1

Thanks for advance

user2575580
  • 1
  • What if the data is unsorted (eg. Tadpole first, Pinwheel last) - would you want two outputs "1 galaxy in level 1", wait until the end of the loop, or sort the data up front? – Mathias R. Jessen Sep 14 '22 at 10:41
  • Use a linq GroupBy and then use property Count() : theGalaxies.GroupBy(x => x.Level).Select(x => new { level = x.Key, count = x.Count()}).ToList(); – jdweng Sep 14 '22 at 10:43
  • @MathiasR.Jessen, Yes, I plan to sort the data first with respect to a property into a list (for instance, level in this example or other property), but maybe there is an elegant way to sort it and group them while print out the info at the same time? – user2575580 Sep 14 '22 at 19:21

1 Answers1

1

Modify your code as like shown below

foreach(var galaxies in theGalaxies.GroupBy(x=>x.Level)){
    foreach(var galaxy in galaxies){
        Console.WriteLine($"{galaxy.Name} {galaxy.MegaLightYears}");
    }   
    Console.WriteLine($"{galaxies.Count()} galaxies in Level {galaxies.Key}");
}

To show proper table on console use link Or below code

static int tableWidth = 73;

static void Main(string[] args)
{
    Console.Clear();
    PrintLine();
    PrintRow("Column 1", "Column 2", "Column 3", "Column 4");
    PrintLine();
    PrintRow("", "", "", "");
    PrintRow("", "", "", "");
    PrintLine();
    Console.ReadLine();
}

static void PrintLine()
{
    Console.WriteLine(new string('-', tableWidth));
}

static void PrintRow(params string[] columns)
{
    int width = (tableWidth - columns.Length) / columns.Length;
    string row = "|";

    foreach (string column in columns)
    {
        row += AlignCentre(column, width) + "|";
    }

    Console.WriteLine(row);
}

static string AlignCentre(string text, int width)
{
    text = text.Length > width ? text.Substring(0, width - 3) + "..." : text;

    if (string.IsNullOrEmpty(text))
    {
        return new string(' ', width);
    }
    else
    {
        return text.PadRight(width - (width - text.Length) / 2).PadLeft(width);
    }
}
Technorg
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