Using a nested foreach to store one foreach value into an array

Question

Alright so I didn't really know how to word this question, but I did my best. The goal I am trying to accomplish is to go through categories using a foreach loop. Inside the category foreach loop another foreach loop will go through Numbers. Right now it is grabbing ever value in the tables and storing them into an array. My goal is to only store the highest number in each category into the array.

Here is how the tables would look:

Category Table  

Title        NumberId

Type            1
Priority        2
Likelihood      3

Numbers Table

Order        NumberId
  3              1
  2              1
  1              1
  3              2
  2              2
  1              2
  3              3
  2              3
  1              3

So my goal would be instead of storing every order value into the array. I would like to store the highest number according to each number id. So there array would include 3,3,3.

This is what I have that stores every number into an array:

int[] values = new int[count];

foreach(var x in Category)
{
   foreach(var w in x.Numbers)
   {
      values[y] = w.Order;
      y++;
   }
}

Solution:

int[] values = new int[count];

foreach(var x in Category)
{
   foreach(var w in x.Numbers)
   {
       values[y] = x.Numbers.Select(o => o.Order).Max();
       y++;
       break;
    }
}

har07 · Accepted Answer · 2014-05-02 01:34:09Z

1

You can use IEnumerable.Max() :

foreach(var x in Category)
{
    values[y] = x.Numbers.Select(o => o.Order).Max();
    y++;
}

answered May 2, 2014 at 1:34

har07

89.5k12 gold badges87 silver badges143 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Shawn Over a year ago

That almost does the trick, but it fills the array with all 3's. So everytume it goes through the loop I am getting the max value of that category

har07 Over a year ago

okay, so in the end the array contains [3,3,3]? isn't that what you are after?

Shawn Over a year ago

Added a break statement on the inner foreach loop with your query. Check my edit for answer.

Ben H · Accepted Answer · 2014-05-02 01:34:33Z

1

This can be accomplished relatively easily through LINQ as:

int[] values = new int[count];

foreach(var x in Category)
{
    values.[y] = x.Numbers.OrderBy(w => w.Order).Reverse().First();
    y++;
}

This orders the x.Numbers by their ascending order, reverses the order (to place the highest value first in the order), and then selects the first value.

Ensure with this method that you've actually got a value for x.Number, else you'll get an exception thrown by the .First() call.

If you're unable to use LINQ (e.g. if you're on .NET 2.0), then consider using a Dictionary with the Category as the key, and the highest Number as the value:

Dictionary<int, int> categoriesByHighestOrders = new Dictionary<int, int>();
foreach(var x in Category)
{
    if (!categoriesByHighestOrders.Keys.Contains[x.SomeIndetifier])
        categoriesByHighestOrders.Add(x.SomeIdentifier, 0);
   foreach(var w in x.Numbers)
   {
        if (categoriesByHighestOrders[x.SomeIndetifier] < w.Order
            categoriesByHighestOrders[x.SomeIndetifier] = w.Order;
   }
}

edited May 2, 2014 at 1:34

answered May 2, 2014 at 1:29

Ben H

4943 silver badges11 bronze badges

2 Comments

Shawn Over a year ago

I like your thinking will definitly use this way. I am getting an error that says 'Cannot implicitly convert type MyApp.Models.Numbers' to 'int'. Any idea?

Ben H Over a year ago

I'm guessing MyApp.Models.Numbers is a type/class you've written? In that case you'll need to make the array of type MyApp.Models.Numbers, or if you're using a dictionary make the dictionary of type Dictionary<MyApp.Models.Numbers, MyApp.Models.Numbers> and write custom comparison logic.

Collectives™ on Stack Overflow

Using a nested foreach to store one foreach value into an array

2 Answers 2

3 Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related