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Using Linq to determine if there is more than 2 distinct items in a class

I have a class that contains a list of another class which has a property that I want to check if it has more than one distinct value.
e.g
public class BasketModel
{
public BasketModel()
{
BasketOrderLines = new List<BasketOrderLine>();
}
.
.
.
public class BasketOrderLine
{
public int OrderLineId { get; set; }
public string ImageUrl { get; set; }
public string ProductType { get; set; }
.
.
Given a basket model object I want to find out if there are more than one distinct value in the ProductType.
e.g If all Product Types are "A" then that would be false, if 3 products are of type "A" and one is of type "B" then this would be true.
Cheers
Macca

Your title: "more than two distinct", your question body: "more than one distinct"
If the title is a typo:
bool notDistinctTypes = theBasket.BasketOrderLine
.Select(o => o.ProductType)
.Distinct()
.Skip(1)
.Any();
This doesn't need to enumerate all items to find out if there is more than one ProductType.

// Does this basket contains three or more types
public bool HasSeveralTypes(BasketModel basket)
{
if (basket == null)
return false;
int differentTypes = basket.BasketOrderLines
.Select(l => l.ProductType)
.Distinct()
.Count();
return (differentTypes > 2);
}

Something like this :
Public bool CheckDistinct (){
var res = basketOrderLines.Select(o => o.ProductType).Distinct ().Count ();
return res > 1;
}

There are a few ways to do this, here's one:
public class BasketModel
{
public BasketModel()
{
BasketOrderLines = new List<BasketOrderLine>();
}
public bool HasMulitpleDistinctProducts
{
get
{
if (!BasketOrderLines.Any())
{
return true; // or false?
}
return BasketOrderLines.Select(b => b.ProductType).Distinct().Count() > 1;
}
}
}

Here is a type extension you can call directly from your list. The pros of this code is to be adaptable to any type implementing IEquals and not only string + kick to use from your code.
The code :
public static class Tools
{
public static bool fDistinctProductType(this List<BasketOrderLine> lstToAnalyse)
{
BasketOrderLine ProductTypeA = lstToAnalyse.FirstOrDefault();
if (ProductTypeA == null) // It's null when lstToAnalyse is empty
return false;
BasketOrderLine ProductTypeB = lstToAnalyse.Where(b => b.ProductType.Equals(ProductTypeA.ProductType)).FirstOrDefault();
if (ProductTypeB == null) // It's null when it doesn't exists a distinct ProductType
return false;
return true;
}
}
How to call:
List<BasketOrderLine> lst = new List<BasketOrderLine>();
// Add element to list
if (lst.fDistinctProductType())
{
// DO Something
}

Iterating through a list of objects and get one index of all objects to a Total

I need to make a loop that iterates through all objects in the list and extracting the value of a specific index and return an Int with the total amount.
I will try to explain as throughly as possible.
public class CostEachActivity
{
public string activityID { get; set; }
public int accountNr { get; set; }
public int amount { get; set; }
}
This is my class which the list contains objects from.
I will send down a string of activityID which I have to return the total cost of from all accounts.
this is the list which contains all the objects(the count is 5 atm)
List<CostEachActivity> dka = new List<CostEachActivity>();
EDIT: This is the working method.
int sum = 0;
List<CostEachActivity> templist = new List<CostEachActivity>();
foreach (CostEachActivity cea in dka)
{
if (cea.activityID == activityID)
templist.Add(cea);
}
foreach(var item in tempList)
{
sum += item.Amount;
}

The Problem
Your inner loop, besides not compiling, should be outside the main loop. After finding all the items you want to sum it (or in a different way to already sum it as you find the matching item.
Also, seeing that you opened a {} after the if and nested the second foreach in it - That scope happens for every item. You if statement, if returns true will execute the adding to the tempList and then, no matter what occurred in the if the second foreach will take place.
if (cea.activityID == activityID) // If this is true
templist.Add(cea); // Then this executes
{ // And this happens in any case
foreach (cea.amount = sum + amount)
}
Possible Solutions
Doing it the way you started:
int sum = 0;
List<CostEachActivity> templist = new List<CostEachActivity>();
foreach (CostEachActivity cea in dka)
{
if (cea.activityID == activityID)
templist.Add(cea);
}
foreach(var item in tempList)
{
sum += item.Amount;
}
Sum the values as you go:
int sum = 0;
foreach (CostEachActivity cea in dka)
{
if (cea.activityID == activityID)
sum += cea.Amount;
}
And IMO the best way: Using linq you can do this:
var sum = dka.Where(item => item.activityID == activityID)
.Sum(item => item.amount);

If I got this right you could do something like:
public int GetSum(string activityId)
{
return dka.Where(cea => cea.activityId == activityId).Sum(cea => cea.amount)
}
Or with the new C# 6.0 Expression-bodied function members:
public int GetSome(string activityId) =>
dka.Where(cea => cea.activityId == activityId)
.Sum(cea => cea.amount);

Use Linq
public int GetSum(string activityID)
{
return dka.Where(d => d.activityID == activityID).Sum(d => d.amount);
}

Sorting a List<> using linq in C#

I would like to do "sorting" under Datagridview ColumnHeaderMouseClick.
Accending or Decending should need to be automatic, selected column value automatic.
I gone through many websites and tried some options but I could not be able to achieve my goal.
private void lst_Install_Item_Main_ColumnHeaderMouseClick(object sender, DataGridViewCellMouseEventArgs e)
{
try
{
DataGridViewColumn newColumn = lst_Install_Item_Main.Columns[e.ColumnIndex];
List<test> temp = (List<test>)lst_Install_Item_Main.DataSource;
//var newList = temp.OrderBy(m => m.feet).ToList();
//var newList = temp.AsQueryable().OrderBy(m => m.feet).ToList();
temp.Sort((m1, m2) => m1.feet.CompareTo(m2.feet));
lst_Install_Item_Main.DataSource = temp;
lst_Install_Item_Main.Refresh();
}
catch (Exception ex)
{
MessageBox.Show("There was an error bringing sorting \n" + ex.Message, "Testing", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
}
Above code "sorting" the list on "feet" column but
I would like to pass the columnname which user clicked, is that possible ?
I have input like (1', 21', 123', 5', 10')
Above code sorting the list like >> (1', 10', 123', 21', 5')
But I want output like >> (1', 5', 10', 21', 123')
Is that possible to achieve ?
How to achieve Ascending or Descending here
(I mean while I clicked first time it will do Ascending and while click on same column second time it should need to do Descending)
Your suggestionshelp are greatly appreciated.

If you don't have negative values, then to sort as you want you need either to parse values as numeric or simply pad them:
temp.Sort((m1, m2) => m1.feet.PadLeft(2).CompareTo(m2.feet.PadLeft(2)));
When comparing strings "1", "5" and "10" this will be comparing " 1", " 5" and "10" instead (notice empty space, which is less than 0 character), making them sorted in the right order.
Make sure to chose number big enough to cover padding to the longest number.

You need to sort the values of feet as integers. To do this, you first need to remove the feet-symbol (') and afterwards parse the value to an int (temporarily, the value is still stored as a string).
This should do the trick:
temp.Sort((m1, m2) => int.Parse(m1.feet.Replace("'", "")).CompareTo(int.Parse(m2.feet.Replace("'", ""))));
Also, I would recommend that you don't store the feet-symbol in the value, and instead use some kind of formatting to include it, when showing the values in the Grid. That way you can avoid these kinds of conversions and comparisons, each time you need to use the values.

You have to convert your strings to integer-values as strings are differently ordered (lexicographically 10 comes before 2). Furtheremore as your input contains '-characters you have to delete them first using String.Trim('\'').
temp.Sort((m1, m2) => Convert.ToInt32(m1.feet.Trim('\'')).CompareTo(Convert.ToInt(m2.feet.Trim('\''))));
Alternativly you may also use Linq-OrderBy:
temp = temp.OrderBy(x => Convert.ToInt32(x.feet.Trim('\''))).ToList();
And OrderByDescending if in descending-order.

UPDATED for question # 3, added trigger for sort order
I would suggest you to use ICoparer in such way
public class TestComparer : IComparer<test>
{
bool isAscending;
public TestComparer(bool isAscendingOrder)
{
isAscending = isAscendingOrder;
}
int IComparer<test>.Compare(test a, test b)
{
int c1 = IntFromStr(a.feet);
int c2 = IntFromStr(b.feet);
int res;
res = (c1 > c2) ? 1 : (c1 < c2) ? -1 : 0;
return isAscending ? res : -res;
}
int IntFromStr(string s)
{
int result;
return (int.TryParse(s.Replace("'", ""), out result)) ? result : int.MaxValue;
}
}
this comparer will move not valid items to the end of the sorted list, also you will be able to change your sort behaviour easily, you will call it like below
List < test > lst = new List<test>();
// It will be your property to Trigger value each time you click
// (sortOrderTrigger = !sortOrderTrigger)
bool sortOrderTrigger = true;
lst.Add(new test { feet = "1'" });
lst.Add(new test { feet = "21'" });
lst.Add(new test { feet = "123'" });
lst.Add(new test { feet = "5'" });
lst.Add(new test { feet = "10'" });
lst.Add(new test { feet = "15'" });
lst.Add(new test { feet = "jj'" });
lst.Add(new test { feet = "ff'" });
lst.Sort(new TestComparer(sortOrderTrigger));

Thanks for all your help and Direction.
I have fixed my requirements as like below, Hope this help to someone like me :)
1. Created list which contains the same columns as the columns dataproperty.
public class sortList
{
public string Layer { get; set; }
public string mlenth { get; set; }
public string diameter { get; set; }
public string subtypecd { get; set; }
public string coatingtype { get; set; }
public string year { get; set; }
public string gisid { get; set; }
public string taxdistrict { get; set; }
public string lengthsource { get; set; }
public string shapelen { get; set; }
public string feet { get; set; }
public sortList()
{
this.Layer = ListSortDirection.Ascending.ToString();
this.mlenth = ListSortDirection.Ascending.ToString();
this.feet = ListSortDirection.Ascending.ToString();
this.diameter = ListSortDirection.Ascending.ToString();
this.subtypecd = ListSortDirection.Ascending.ToString();
this.coatingtype = ListSortDirection.Ascending.ToString();
this.year = ListSortDirection.Ascending.ToString();
this.gisid = ListSortDirection.Ascending.ToString();
this.taxdistrict = ListSortDirection.Ascending.ToString();
this.lengthsource = ListSortDirection.Ascending.ToString();
this.shapelen = ListSortDirection.Ascending.ToString();
}
}
2. Written code on ColumnHeaderMouseClick event and order function
private void lst_Install_Item_Main_ColumnHeaderMouseClick(object sender, DataGridViewCellMouseEventArgs e)
{
try
{
//Get Column which clicked
DataGridViewColumn newColumn = lst_Install_Item_Main.Columns[e.ColumnIndex];
//Get Values from DataGrid
List<test> temp = (List<test>)lst_Install_Item_Main.DataSource;
//Get the sorting order for that column
string orderby = GetOrder(newColumn.DataPropertyName);
if (orderby == ListSortDirection.Ascending.ToString()) //Ascending
{
if (newColumn.DataPropertyName == "feet") //Feet column sort with double value and required trim
{
temp = temp.OrderBy(x => Convert.ToDouble(x.feet.Trim('\''))).ToList();
}
else if (newColumn.DataPropertyName == "shapelen") //Shapelen column sort with double value and required trim
{
temp = temp.OrderBy(x => Convert.ToDouble(x.shapelen.Trim('\''))).ToList();
}
else ///other columns having string value only.
{
temp = temp.OrderBy(x => x.GetType().GetProperty(newColumn.DataPropertyName).GetValue(x, null)).ToList();
}
}
else // Descending
{
if (newColumn.DataPropertyName == "feet") //Feet column sort with double value and required trim
{
temp = temp.OrderByDescending(x => Convert.ToDouble(x.feet.Trim('\''))).ToList();
}
else if (newColumn.DataPropertyName == "shapelen") //Shapelen column sort with double value and required trim
{
temp = temp.OrderByDescending(x => Convert.ToDouble(x.shapelen.Trim('\''))).ToList();
}
else //other columns having string value only.
{
temp = temp.OrderByDescending(y => y.GetType().GetProperty(newColumn.DataPropertyName).GetValue(y, null)).ToList();
}
}
lst_Install_Item_Main.DataSource = temp;
lst_Install_Item_Main.Refresh();
}
catch (Exception ex)
{
MessageBox.Show("There was an error while sorting \n" + ex.Message, "Closeout Calculator", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
}
private string GetOrder(string columnName)
{
//Store the each coulmn(Ascending/Descending) values to make it dynamic
string ord = sortOrder[0].GetType().GetProperty(columnName).GetValue(sortOrder[0], null).ToString();
if (ord == ListSortDirection.Ascending.ToString())
{
sortOrder[0].GetType().GetProperty(columnName).SetValue(sortOrder[0], ListSortDirection.Descending.ToString(), null);
}
else
{ sortOrder[0].GetType().GetProperty(columnName).SetValue(sortOrder[0], ListSortDirection.Ascending.ToString(), null); }
return ord;
}
3. sortoder list initialize and obj declared at Constructor.
Private List<sortList> sortOrder = new List<sortList>();
sortOrder.Add(new sortList());

Is there a var.contains - C#

I have a question about the following code:
private void Filter (object sender, Android.Text.TextChangedEventArgs e)
{
List<Animal> animalList = new List<Animal>();
if(!string.IsNullOrEmpty(_editText.Text))
{
foreach (string str in _animalList)
{
if (str.Contains(_editText.Text))
{
animalList.Add (str);
}
}
}
_listView.Adapter = new AnimalAdapter(this, _animalList = animalList);
}
The Animal class:
public class Animal
{
private readonly int _intKey;
public int AnimalNumber { get; private set; }
public int StableNumber { get; private set; }
public int LactoseNumber { get; private set; }
public Animal ( int intKey, int animalNumber, int stableNumber, int lactoseNumber )
{
_intKey = intKey;
AnimalNumber = animalNumber;
StableNumber = stableNumber;
LactoseNumber = lactoseNumber;
}
public override string ToString ()
{
return "Number: " + AnimalNumber + "\nGroup: " + StableNumber + "\nLactation: " + LactoseNumber;
}
}
Declaration of _animalList:
private List<Animal> _animalList;
i need to check if the _animalList Contains the input of the _editText.Text.
But _animalList isn't a string so i need to use a var.
Is there something like a var.Contains or do i have to use something else?

Contains method is available for string type. You will need to cast your object to string.
A/c to your class definition you should do like:
foreach (Animal str in _animalList)
{
if (str.ToString().Contains(_editText.Text)) //using user defined "ToString()"
{
animalList.Add (str);
}
}
You can also check individual properties:
foreach (Animal str in _animalList)
{
if (str.AnimalNumber.ToString().Contains(_editText.Text)) //if "AnimalNumber" is like "_editText.Text"
{
animalList.Add (str);
}
}

Instead of trying to filter using ToString, it would be better to use the real property values. For example:
var number = Convert.ToInt32(_editText.Text);
var filteredList = _animalList
.Where(x => x.AnimalNumber == number ||
x.StableNumber == number ||
x.LactoseNumber == number)
.ToList();
Otherwise, user could type "Number" and since your ToString override contains that string, all of the items in the list would match positively.
(I didn't include any validation or error checking in the code above, so you should consider those as well).

var inputText = _editText.Text;
int enteredNumber;
// you should make sure that the inputText is always an int
var isInt = int.TryParse(inputText, out enteredNumber);
//for example, if you are going to find by AnimalNumber, which is an int, you can use this. .
if (isInt){
foreach (var animal in _animalList){
var animalNumber = animal.AnimalNumber;
if (animalNumber == enteredNumber)
{
animalList.Add(animal);
}
}
}
Edit (LINQ alternative):
if (isInt){
animalList.AddRange(from animal in _animalList
let animalNumber = animal.AnimalNumber
where animalNumber == enteredNumber
select animal);
}

_animalList.Select(a => a.ToString()).Contains(_editText.Text)
This expression returns true if the output of the ToString method of any animal object equals _editText.Text.
_animalList.Select(a => a.ToString()).Any(str => str.Contains(_editText.Text))
This expression returns true if the output of the ToString method of any animal object contains _editText.Text (as a substring). This is equivalent to Shaharyar's answer.
var animalList = _animalList.Where(a => a.ToString().Equals(_editText.Text)).ToList();
var animalList = _animalList.Where(a => a.ToString().Contains(_editText.Text)).ToList();
These statements filter the input list directly.

traveling salesman problem, 2-opt algorithm c# implementation

Can someone give me a code sample of 2-opt algorithm for traveling salesman problem. For now im using nearest neighbour to find the path but this method is far from perfect, and after some research i found 2-opt algorithm that would correct that path to the acceptable level. I found some sample apps but without source code.

So I got bored and wrote it. It looks like it works, but I haven't tested it very thoroughly. It assumes triangle inequality, all edges exist, that sort of thing. It works largely like the answer I outlined. It prints each iteration; the last one is the 2-optimized one.
I'm sure it can be improved in a zillion ways.
using System;
using System.Collections.Generic;
using System.Linq;
namespace TSP
{
internal static class Program
{
private static void Main(string[] args)
{
//create an initial tour out of nearest neighbors
var stops = Enumerable.Range(1, 10)
.Select(i => new Stop(new City(i)))
.NearestNeighbors()
.ToList();
//create next pointers between them
stops.Connect(true);
//wrap in a tour object
Tour startingTour = new Tour(stops);
//the actual algorithm
while (true)
{
Console.WriteLine(startingTour);
var newTour = startingTour.GenerateMutations()
.MinBy(tour => tour.Cost());
if (newTour.Cost() < startingTour.Cost()) startingTour = newTour;
else break;
}
Console.ReadLine();
}
private class City
{
private static Random rand = new Random();
public City(int cityName)
{
X = rand.NextDouble() * 100;
Y = rand.NextDouble() * 100;
CityName = cityName;
}
public double X { get; private set; }
public double Y { get; private set; }
public int CityName { get; private set; }
}
private class Stop
{
public Stop(City city)
{
City = city;
}
public Stop Next { get; set; }
public City City { get; set; }
public Stop Clone()
{
return new Stop(City);
}
public static double Distance(Stop first, Stop other)
{
return Math.Sqrt(
Math.Pow(first.City.X - other.City.X, 2) +
Math.Pow(first.City.Y - other.City.Y, 2));
}
//list of nodes, including this one, that we can get to
public IEnumerable<Stop> CanGetTo()
{
var current = this;
while (true)
{
yield return current;
current = current.Next;
if (current == this) break;
}
}
public override bool Equals(object obj)
{
return City == ((Stop)obj).City;
}
public override int GetHashCode()
{
return City.GetHashCode();
}
public override string ToString()
{
return City.CityName.ToString();
}
}
private class Tour
{
public Tour(IEnumerable<Stop> stops)
{
Anchor = stops.First();
}
//the set of tours we can make with 2-opt out of this one
public IEnumerable<Tour> GenerateMutations()
{
for (Stop stop = Anchor; stop.Next != Anchor; stop = stop.Next)
{
//skip the next one, since you can't swap with that
Stop current = stop.Next.Next;
while (current != Anchor)
{
yield return CloneWithSwap(stop.City, current.City);
current = current.Next;
}
}
}
public Stop Anchor { get; set; }
public Tour CloneWithSwap(City firstCity, City secondCity)
{
Stop firstFrom = null, secondFrom = null;
var stops = UnconnectedClones();
stops.Connect(true);
foreach (Stop stop in stops)
{
if (stop.City == firstCity) firstFrom = stop;
if (stop.City == secondCity) secondFrom = stop;
}
//the swap part
var firstTo = firstFrom.Next;
var secondTo = secondFrom.Next;
//reverse all of the links between the swaps
firstTo.CanGetTo()
.TakeWhile(stop => stop != secondTo)
.Reverse()
.Connect(false);
firstTo.Next = secondTo;
firstFrom.Next = secondFrom;
var tour = new Tour(stops);
return tour;
}
public IList<Stop> UnconnectedClones()
{
return Cycle().Select(stop => stop.Clone()).ToList();
}
public double Cost()
{
return Cycle().Aggregate(
0.0,
(sum, stop) =>
sum + Stop.Distance(stop, stop.Next));
}
private IEnumerable<Stop> Cycle()
{
return Anchor.CanGetTo();
}
public override string ToString()
{
string path = String.Join(
"->",
Cycle().Select(stop => stop.ToString()).ToArray());
return String.Format("Cost: {0}, Path:{1}", Cost(), path);
}
}
//take an ordered list of nodes and set their next properties
private static void Connect(this IEnumerable<Stop> stops, bool loop)
{
Stop prev = null, first = null;
foreach (var stop in stops)
{
if (first == null) first = stop;
if (prev != null) prev.Next = stop;
prev = stop;
}
if (loop)
{
prev.Next = first;
}
}
//T with the smallest func(T)
private static T MinBy<T, TComparable>(
this IEnumerable<T> xs,
Func<T, TComparable> func)
where TComparable : IComparable<TComparable>
{
return xs.DefaultIfEmpty().Aggregate(
(maxSoFar, elem) =>
func(elem).CompareTo(func(maxSoFar)) > 0 ? maxSoFar : elem);
}
//return an ordered nearest neighbor set
private static IEnumerable<Stop> NearestNeighbors(this IEnumerable<Stop> stops)
{
var stopsLeft = stops.ToList();
for (var stop = stopsLeft.First();
stop != null;
stop = stopsLeft.MinBy(s => Stop.Distance(stop, s)))
{
stopsLeft.Remove(stop);
yield return stop;
}
}
}
}

Well, your solution to TSP is always going to be far from perfect. No code, but here's how to go about 2-Opt. It's not too bad:
You need a class called Stop that has a Next, Prev, and City property, and probably a Stops property that just returns the array containing Next and Prev.
When you link them together, we'll call that a Tour. Tour has a Stop property (any of the stops will do), and an AllStops property, whose getter just walks the stops and returns them
You need a method that takes a tour and returns its cost. Let's call that Tour.Cost().
You need Tour.Clone(), which just walks the stops and clones them individually
You need a method that generates the set of tours with two edges switched. Call this Tour.PossibleMutations()
Start with your NN solution
Call PossibleMutations() on it
Call Cost() on all of them and take the one with the lowest result
Repeat until the cost doesn't go down

If the problem is euclidian distance and you want the cost of the solution produced by the algorithm is within 3/2 of the optimum then you want the Christofides algorithm. ACO and GA don't have a guaranteed cost.