I am making a group by linq statement where i convert a single list of data into an list with a nested list. Here is my code so far:
[TestMethod]
public void LinqTestNestedSelect2()
{
// initialization
List<combi> listToLinq = new List<combi>() {
new combi{ id = 1, desc = "a", name = "A", count = 1 },
new combi{ id = 1, desc = "b", name = "A", count = 2 },
new combi{ id = 2, desc = "c", name = "B", count = 3 },
new combi{id = 2, desc = "d", name = "B", count = 4 },
};
// linq group by
var result = (from row in listToLinq
group new { des = row.desc, count = row.count } by new { name = row.name, id = row.id } into obj
select new A { name = obj.Key.name, id = obj.Key.id, descriptions = (from r in obj select new B() { des = r.des, count = r.count }).ToList() }).ToList();
// validation of the results
Assert.AreEqual(2, result.Count);
Assert.AreEqual(2, result[0].descriptions.Count);
Assert.AreEqual(2, result[0].descriptions.Count);
Assert.AreEqual(2, result[1].descriptions.Count);
Assert.AreEqual(2, result[1].descriptions.Count);
}
public class A
{
public int id;
public string name;
public List<B> descriptions;
}
public class B
{
public int count;
public string des;
}
public class combi
{
public int id;
public string name;
public int count;
public string desc;
}
This is fine if the objects are small like the example. However I will implement this for objects with a lot more properties. How can I efficiently write this statement so I don't have to write field names twice in my linq statement?
I would like to return the objects in the statement and I want something like:
// not working wishfull thinking code
var result = (from row in listToLinq
group new { des = row.desc, count = row.count } by new { name = row.name, id = row.id } into obj
select new (A){ this = obj.key , descriptions = obj.ToList<B>()}).ToList();
Background: I am re writing a web api that retrieves objects with nested objects in a single database call for the sake of db performance. It's basically a big query with a join that retrieves a crap load of data which I need to sort out into objects.
probably important: the ID is unique.
EDIT:
based on the answers so far I have made a solution which sort of works for me, but is still a bit ugly, and I would want it to be better looking.
{
// start part
return (from row in reader.AsEnumerable()
group row by row.id into grouping
select CreateA(grouping)).ToList();
}
private static A CreateA(IGrouping<object, listToLinq> grouping)
{
A retVal = StaticCreateAFunction(grouping.First());
retVal.descriptions = grouping.Select(item => StaticCreateBFunction(item)).ToList();
return ret;
}
I hope the StaticCreateAFunction is obvious enough for what it does. In this scenario I only have to write out each property once, which is what I really wanted. But I hope there is a more clever or linq-ish way to write this.
var result = (from row in listToLinq
group new B { des = row.desc, count = row.count } by new A { name = row.name, id = row.id } into obj
select new A { name = obj.Key.name, id = obj.Key.id, descriptions = obj.ToList() }).ToList();
You can add to each of the A and B classes a constructor that receives a combi and then it takes from it only what it needs. For example for a:
public class A
{
public A(combi c)
{
id = c.id;
name = c.name;
}
}
public class B
{
public B(combi c)
{
count = c.count;
des = c.desc;
}
}
Then your query can look like:
var result = (from row in listToLinq
group row by new { row.id, row.name } into grouping
select new A(grouping.First())
{
descriptions = grouping.Select(item => new B(item)).ToList()
}).ToList();
If you don't like the grouping.First() you can then override Equals and GetHashCode and then in the group by do by a new a with the relevant fields (which will be those in the Equals) and then add a copy constructor from a
Another way, in which you decouple the A/B classes from the combi is to extract the convert logic to a collection of static methods.
Related
My first post. Humbled by this community. Thank you.
The goal: Create a new List<PropertyB> based on two other lists:
List<PropertyA> and another List<PropertyB>.
For each PropertyA in the List<PropertyA>, create a new PropertyB(), assigning the DisplayName to the new PropertyB's Name property. For each property in 'List', if the name from PropertyA matches PropertyB, assign the value to the new list's value property.
The problem: Accounting for Duplicate values. No data loss can occur between the lists.
The new list should include: Every PropertyA and every Value of the PropertyB list where there is a Name match.
The types:
My thoughts: My gut says the inner loop should check whether something has already been added to the collection. Or perhaps an accounting of duplicate values (ie: the index of duplicates?)
Any assistance is appreciated!
public class PropertyA{
private string DisplayName{get; set;}
private string Name {get; set;}
private string Value {get; set;}
}
public class PropertyB{
private string Name{get; set;}
private string Value{get; set;}
}
Initialization:
List<PropertyA> listA = new List<PropertyA>()
{
new PropertyA(){ DisplayName="LOB", Name="lineofbusiness", Value="test"},
new PropertyA(){ DisplayName="ABC", Name="alpha", Value="test2"},
new PropertyA(){ DisplayName="DEF", Name="beta", Value="test3"},
new PropertyA(){ DisplayName="GHI", Name="zeta", Value="test4"},
new PropertyA(){ DisplayName"Line of Business", Name="lineofbusiness", Value="test5"
};
List<PropertyB> listB = new List<PropertyB>()
{
new PropertyB(){ Name="lineofbusiness", Value="test789"},
new PropertyB(){ Name="alpha", Value="test234"},
new PropertyB(){ Name="lineofbusiness", Value="test456"},
new PropertyB(){ Name="beta", Value="test123"},
};
In Main:
List<PropertyB> newList = new List<PropertyB>();
foreach(PropertyA propA in listA){
PropertyB newProp = new PropertyB();
newProp.Name = propA.DisplayName;
foreach(PropertyB propB in listB){
if(propA.Name == propB.Name){
newProp.Value = propB.Value;
break;
}
}
newList.Add(newProp);
}
UPDATE:
The console output (if you choose) should be as follows:
LOB test789
ABC test234
DEF test123
GHI null
Line of Business test456
if you simply remove the break; you end up with:
LOB test456
ABC test234
DEF test123
GHI null
Line of Business test456
The inner loop will always assign the LAST name match value. That's a problem.
you can just fix your code, add a check for duplicates
List<PropertyB> newList = new List<PropertyB>();
foreach(PropertyA propA in listA)
{
PropertyB newProp = new PropertyB();
newProp.Name = propA.DisplayName;
foreach (var propB in listB)
{
if (propA.Name == propB.Name)
{
if( newList.Any(l =>l.Value==propB.Value )) continue;
newProp.Value = propB.Value;
break;
}
}
newList.Add(newProp);
}
but to make it more reliable I would offer this
List<PropertyA> newList = new List<PropertyA>();
foreach (var propA in listA)
{
var newProp = new PropertyA();
newProp.Name = propA.DisplayName;
newProp.DisplayName = propA.Name;
foreach (var propB in listB)
{
if (propA.Name == propB.Name)
{
if (newList.Any(l => l.Value == propB.Value
&& l.DisplayName==propA.Name)) continue;
newProp.Value = propB.Value;
break;
}
}
newList.Add(newProp);
}
var result = newList.Select(l => new PropertyB {Name=l.Name, Value=l.Value} );
both algorithms show the same result during the test
LOB test789
ABC test234
DEF test123
GHI null
Line of Business test456
I understood the process:
list of A needs turning into a list of B
Some of the list of B items might have a Value copied from some other list of B
var d = bList.ToDictionary(b => b.Name, b => b.Value);
var newB = aList.Select(a => new B { Name = a.DisplayName, Value = d.GetValueOrDefault(a.Name) } ).ToList();
You said no data shall be lost but I think inherently you must have to throw something away because B has fewer properties than A and some properties from B are used to "overwrite"/take the place of those in A..
I note also you have duplicated Name in your sample data list B, which the ToDictionary won't tolerate. You didn't specify how to resolve this but you'll have to choose (if it truly does occur) what value to pick or if to take multiple. This, for example, would tolerate duplicate names
var d = bList.ToLookup(b => b.Name, b => b.Value);
var newB = aList.Select(a => new B { Name = a.DisplayName, Value = d[a.Name]?.First() } ).ToList();
Again, this throws stuff away.. if you want to keep all the values you'll have to encode the Value somehow
Value = string.Join(",", d[a.Name])
for example
So, it looks like you want to keep all the duplicates and dispense them in order. We could do that by grouping these things into a list that we pull the items out of as we enumerate
var d = bList.GroupBy(b => b.Name, b => b.Value).ToDictionary(g => g.Key, g => g.ToList());
var newB = new List<B>();
foreach(var a in aList){
var b = new B { Name = a.DisplayName };
if(d.TryGetValue(a.Name, out var lst)){
b.Value = lst[0];
lst.RemoveAt(0);
}
}
I have LINQ query that I want to generate dynamically:
var groupData =
from l in data
group l by l.Field1 into field1Group
select new MenuItem()
{
Key = field1Group.Key,
Count = field1Group.Count(),
Items = (from k in field1Group
group k by k.Field2 into field2Group
select new MenuItem()
{
Key = field2Group.Key,
Count = field2Group.Count()
}).ToList()
};
The ultimate goal is to be able to dynamically group the data by any combination of fields with no limit on the nested queries.
I can get as far as the first level but I'm struggling with the nested sub queries:
string field1 = "Field1";
string field2 = "Field2";
var groupDataD =
data.
GroupBy(field1, "it").
Select("new ( it.Key, it.Count() as Count )");
Is this possible with chained dynamic LINQ? Or is there a better way to achieve this?
The following should work (though personally I would rather avoid using such code):
Follow this answer to add the following in ParseAggregate, :
Expression ParseAggregate(Expression instance, Type elementType, string methodName, int errorPos)
{
// Change starts here
var originalIt = it;
var originalOuterIt = outerIt;
// Change ends here
outerIt = it;
ParameterExpression innerIt = Expression.Parameter(elementType, elementType.Name);
it = innerIt;
Expression[] args = ParseArgumentList();
// Change starts here
it = originalIt;
outerIt = originalOuterIt;
// Change ends here
...
}
Add Select, GroupBy, ToList into IEnumerableSignatures, and respective conditions in ParseAggregate, as explained in this answer:
interface IEnumerableSignatures
{
...
void GroupBy(object selector);
void Select(object selector);
void ToList();
...
}
Expression ParseAggregate(Expression instance, Type elementType, string methodName, int errorPos)
{
...
if (signature.Name == "Min" ||
signature.Name == "Max" ||
signature.Name == "GroupBy" ||
signature.Name == "Select")
...
}
Finally, Your query would be:
string field1 = "Field1";
string field2 = "Field2";
var result =
data
.GroupBy(field1, "it")
.Select($#"new (
it.Key,
it.Count() as Count,
it.GroupBy({field2})
.Select(new (it.Key, it.Count() as Count))
.ToList() as Items
)");
Note that "it" holds a different instance when used in the parent query vs. the subquery. I tried to take advantage of "outerIt" to overcome this conflation, but unfortunately without success (but maybe you'd succeed? maybe 1, 2 would help)
A simple example for future reference:
public class Person
{
public string State { get; set; }
public int Age { get; set; }
}
public static Main()
{
var persons = new List<Person>
{
new Person { State = "CA", Age = 20 },
new Person { State = "CA", Age = 20 },
new Person { State = "CA", Age = 30 },
new Person { State = "WA", Age = 60 },
new Person { State = "WA", Age = 70 },
};
var result = persons
.GroupBy("State", "it")
.Select(#"new (
it.Key,
it.Count() as Count,
it.GroupBy(Age)
.Select(new (it.Key, it.Count() as Count))
.ToList() as Items
)");
foreach (dynamic group in result)
{
Console.WriteLine($"Group.Key: {group.Key}");
foreach (dynamic subGroup in group.Items)
{
Console.WriteLine($"SubGroup.Key: {subGroup.Key}");
Console.WriteLine($"SubGroup.Count: {subGroup.Count}");
}
}
}
Is there a way to compare 2 models and only show the differences, for example what has been updated, added or deleted?
For example, in the models below, I have created a number of Sample models:
var grocers1 = new List<Grocer>();
var grocer1 = new Grocer
{
Id = 1,
Expenditure = 500,
Name = "Bob"
};
grocers1.Add(grocer1);
var grocers2 = new List<Grocer>();
var grocer2 = new Grocer
{
Id = 1,
Expenditure = 300,
Name = "Bob"
};
grocers2.Add(grocer2);
var fruits = new List<Fruit>();
var fruit1 = new Fruit();
fruits.Add(fruit1);
var orders1 = new List<Order>();
var order1 = new Order
{
Id = 1,
SampleId = 1,
Fruits = fruits
};
var order2 = new Order
{
Id = 1,
SampleId = 1,
Fruits = fruits
};
orders1.Add(order1);
orders1.Add(order2);
var orders2 = new List<Models.Documents.Order> {order1};
var sample = new Sample
{
Id = 1,
Date = Convert.ToDateTime("2018-10-23"),
Grocers = grocers1,
Orders = orders1
};
var changedSample = new Sample
{
Id = 1,
Date = Convert.ToDateTime("2018-10-22"),
Grocers = grocers2,
Orders = orders1
};
var otherChangedSample = new Sample
{
Id = 1,
Date = Convert.ToDateTime("2018-10-23"),
Grocers = grocers1,
Orders = orders2
};
So if I compare sample to changedSample it should just show the Date has changed from 2018-10-23 to 2018-10-22 and that the Expenditure has changed from 500 to 300.
Then if I was to compare sample to otherChangedSample it should show that order2 has been removed.
And then finally if I was to compare otherChangedSample to sample it would show that order 2 had been added.
I have tested with AutoMapper this is great for comparing the same base model, excluding lists, it nicely highlights the changes.
I then tried Compare-Net-Objects which is good, this time does take into account lists and highlights the changes, but only if the list count stays the same. It will identify the list count change but not tell you the values of what has been removed or the values of what has been added.
Any help would be much appreciated.
You can use reflection and extension method as well:
var sample = new Sample
{
Id = 1,
Date = Convert.ToDateTime("2018-10-23"),
Grocers = grocers1,
Orders = orders1
};
var otherChangedSample = new Sample
{
Id = 1,
Date = Convert.ToDateTime("2018-10-23"),
Grocers = grocers1,
Orders = orders2
};
class Variance
{
public string Prop { get; set; }
public object valA { get; set; }
public object valB { get; set; }
}
List<Variance> rt = sample.DetailedCompare(otherChangedSample);
using System.Collections.Generic;
using System.Reflection;
static class extentions
{
public static List<Variance> DetailedCompare<T>(this T val1, T val2)
{
List<Variance> variances = new List<Variance>();
FieldInfo[] fi = val1.GetType().GetFields();
foreach (FieldInfo f in fi)
{
Variance v = new Variance();
v.Prop = f.Name;
v.valA = f.GetValue(val1);
v.valB = f.GetValue(val2);
if (!v.valA.Equals(v.valB))
variances.Add(v);
}
return variances;
}
}
have you coded your model classes yourself? If not, then you have to deal with reflection (could be slow and you have to do a lot of programming to cover all data types), or with serialization (serialize as string and do a string compare).
If you can extend your classes, then I would add a method to every single class:
internal void TrackChange(T other, List<Change> changes)
This method in your class Sampe would look like:
void TrackChange(Sample other, List<Change> changes)
{
if (this.Id != other.Id) changes.add(new Change(...));
if (this.Date != other.Date) changes.add(new Change(...));
if (this.Grocers.count != other.Grocers.count) changes.add(new Change(...)); // number of items has changed
for (int i = 0; i < math.min(this.grocers.count, other.grocers.count); i++)
this.grocers[i].TrackChange(other.grocers[i], changes);
....
}
The Grocer class has its onwn TrackChange method. and so on.
This is some coding, but the most efficient and you can handle all cases yourself. for example if the order of grocers in your list does not mind, then you can iterate all grocers of this list and try to find the corresponding grocer in the others list (e.g. by Id) and call the TrackChange then.
In C#,I have List of Employee object. Employee class is
public class Employee
{
public int ID { get; set; }
public string Name { get; set; }
}
In List objected are sorted based on Employee.ID. I have an array of int which is basically Employee.ID which I want on top of the list and in list,order must remain same as in array.
If I hava input like this
List:
[
{ID:1,Name:A},
{ID:2,Name:B},
{ID:3,Name:AA},
{ID:4,Name:C},
{ID:5,Name:CD},
.
.
{ID:100,Name:Z}
]
and Array: {2,3,1}
Then I want Output List:
[
{ID:2,Name:B},
{ID:3,Name:AA},
{ID:1,Name:A},
{ID:4,Name:C},
{ID:5,Name:CD},
.
.
{ID:100,Name:Z}
]
And I have done this
foreach (int i in a)
{
list = list.OrderBy(x => x.ID != i).ToList();
}
//a is array
//list is List
Any better Solution.Thanks in advance.
After you got your list sorted based on the ID just iterate the array and move the elements. In order to do this you need to first remove and then insert the item at the correct position.
for(int i = 0; i < myArray.Length; i++)
{
var e = myList.Single(x => x.Id == myArray[i]);
myList.Remove(e);
myList.Insert(i, e);
}
You may also want to use SingleOrDefault instead of Single to verify that myList even contains the element with the current id, e.g. when your array contains [2, 3, 101]
To add another version to the mix. The complete sorting can be done in one go:
list = list.OrderBy(e=> {int i =Array.IndexOf(a, e.ID); return i == -1 ? int.MaxValue : i; }).ToList();
where list is the EmployeeList and a the indices array. (NB, the for loop is not needed, the above should do both sortings).
Inside the OrderBy callback, if the id is not inside a, int.MaxValue is returned to place it after the ones inside the array (a.Length would work as well). OrderBy should maintain the original order of the enumeration (list) for those elements that return the same value.
PS, if you want to sort first by index inside a and the rest on the ids (not necessarily the original order), you can use the following (as long as a.Length + largest ID < int.MaxValue) : list = list.OrderBy(e=> {int i =Array.IndexOf(a, e.ID); return i == -1 ? a.Length + e.ID : i; }).ToList();
Here's a way to do it in pure LINQ, without changing the original sequence.
Broken into steps to see what's going on.
public static void Main()
{
var employeeList = new List<Employee>()
{
new Employee(){ ID= 1,Name= "A"},
new Employee() { ID= 2,Name= "B"},
new Employee() { ID= 3,Name= "AA"},
new Employee() { ID= 4,Name= "C"},
new Employee() { ID= 5,Name= "CD"},
new Employee() { ID= 100,Name= "Z"}
};
var orderByArray = new int[] { 2, 3, 1, 100, 5, 4 };
var sortPos = orderByArray.Select((i, index) => new { ID = i, SortPos = index });
var joinedList = employeeList.Join(sortPos, e => e.ID, sp => sp.ID, (e, sp) => new { ID = e.ID, Name = e.Name, SortPos = sp.SortPos });
var sortedEmployees = joinedList.OrderBy(e => e.SortPos).Select(e => new Employee { ID = e.ID, Name = e.Name });
}
Try this using LINQ:
List<Employee> employees = ...
int[] ids = ...
var orderEmployees = ids.Select(id => employees.Single(employee => employee.ID == id))
.Concat(employees.Where(employee => !ids.Contains(employee.ID)).ToList();
Foreach id in ids array we will grab the matching employee and we will concat to it all the employees that their id does not exist in ids array.
I like to use a special Comparer for that, it seems clearer to me, though a bit more code. It hides the complexity of the sort in the comparer class, and then you can just call it with :
theList.OrderBy(x => x.id, new ListOrderBasedComparer(sortList));
It will sort according to any list passed to the comparer when instantiating, and will put elements not in the "known sort list" at the end.
You can of course adapt it to your special needs.
public class ListOrderBasedComparer: Comparer<int>
{
private List<int> sortList;
public ListOrderBasedComparer(List<int> sortList)
{
// if you want you can make constructor accept arrays and convert it
// (if you find that more convenient)
this.sortList = sortList;
}
public override int Compare(int x, int y)
{
var indexOfX = sortList.FindIndex(a => a == x);
var indexOfY = sortList.FindIndex(a => a == y);
// handle elements not in sortArray : if not in sort array always assume they should be "less than the others" and "equal between them".
if (indexOfX == -1 && indexOfY == -1) return 0;
if (indexOfY == -1) return -1;
if (indexOfX == -1) return 1;
// if elements are in sortArray (FindIndex returned other than -1), use usual comparison of index values
return indexOfX.CompareTo(indexOfY);
}
}
Example on how to use it, with Linq :
public class TestCompare
{
public void test ()
{
var myArray = new MyClass[]
{
new MyClass { id = 1, name = "A" },
new MyClass { id = 2, name = "B" },
new MyClass { id = 3, name = "C" },
new MyClass { id = 4, name = "D" },
new MyClass { id = 5, name = "E" },
new MyClass { id = 6, name = "F" },
};
var myArray2 = new MyClass[]
{
new MyClass { id = 1, name = "A" },
new MyClass { id = 2, name = "B" },
new MyClass { id = 0, name = "X" },
new MyClass { id = 3, name = "C" },
new MyClass { id = 4, name = "D" },
new MyClass { id = 23, name = "Z"},
new MyClass { id = 5, name = "E" },
new MyClass { id = 6, name = "F" },
};
var sortList = new List<int> { 2, 3, 1, 4, 5, 6 };
// good order
var mySortedArray = myArray.OrderBy(x => x.id, new ListOrderBasedComparer(sortList)).ToList();
// good order with elem id 0 and 23 at the end
var mySortedArray2 = myArray2.OrderBy(x => x.id, new ListOrderBasedComparer(sortList)).ToList();
}
}
public class MyClass
{
public int id;
public string name;
}
In this example class IcdPatient represents a many-to-many relationship between a Patient table (not shown in this example) and a lookup table Icd.
public class IcdPatient
{
public int PatientId { get; set; }
public int ConditionCode { get; set; }
public static List<IcdPatient> GetIcdPatientList()
{
return new List<IcdPatient>()
{
new IcdPatient { PatientId = 100, ConditionCode = 111 },
new IcdPatient { PatientId = 100, ConditionCode = 222 },
new IcdPatient { PatientId = 200, ConditionCode = 111 },
new IcdPatient { PatientId = 200, ConditionCode = 222 },
new IcdPatient { PatientId = 3, ConditionCode = 222 },
};
}
}
public class Icd
{
public int ConditionCode { get; set; }
public string ConditionName { get; set; }
public static List<Icd> GetIcdList()
{
return new List<Icd>()
{
new Icd() { ConditionCode =111, ConditionName ="Condition 1"},
new Icd() { ConditionCode =222, ConditionName ="Condition 2"},
};
}
}
I would like for the user to be able to enter as many conditions as they want, and get a LINQ object back that tells them how many PatientIds satisfy that query. I've come up with:
List<string> stringFilteredList = new List<string> { "Condition 1", "Condition 2" };
List<int> filteringList = new List<int> { 111,222 };
var manyToMany = IcdPatient.GetIcdPatientList();
var icdList = Icd.GetIcdList();
/*Working method without joining on the lookup table*/
var grouped = from m in manyToMany
group m by m.PatientId into g
where g.Count() == filteringList.Distinct().Count()
select new
{
PatientId = g.Key,
Count = g.Count()
};
/*End*/
foreach (var item in grouped)
{
Console.WriteLine(item.PatientId);
}
Let's say that IcdPatient has a composite primary key on both fields, so we know that each row is unique. If we find the distinct number of entries in filteringList and do a count on the number of times a PatientId shows up, that means we've found all the people who have all conditions. Because the codes can be esoteric, I would like to do something like
let the user table in the ConditionName in type Icd and perform the same operation. I've not used LINQ this way a lot and I've gathered:
List<int> filteringList = new List<int> { 111,222 };
List<string> stringFilteredList= new List<string>{"Condition 1","Condition 2" };
filteringList.Distinct();
var manyToMany = IcdPatient.GetIcdPatientList();
var icdList = Icd.GetIcdList();
/*Working method without joining on the lookup table*/
var grouped = from m in manyToMany
join i in icdList on
m.ConditionCode equals i.ConditionCode
//group m by m.PatientId into g
group new {m,i} by new { m.ConditionCode }into g
where g.Count() == filteringList.Distinct().Count()
select new
{
Condition = g.Key.ConditionCode
};
/*End*/
but can't get anything to work. This is essentially a join on top of my first query, but I'm not getting what I need to group on.
You don't need to group anything in this case, just use a join and a contains:
List<string> stringFilteredList= new List<string>{"Condition 1","Condition 2" };
var patients =
from icd in Icd.GetIcdList()
join patient in IcdPatient.GetIcdPatientList() on icd.ConditionCode equals patient.ConditionCode
where stringFilteredList.Contains(icd.ConditionName)
select patient.PatientId;
Let's say that IcdPatient has a composite primary key on both fields, so we know that each row is unique. If we find the distinct number of entries in filteringList and do a count on the number of times a PatientId shows up, that means we've found all the people who have all conditions. Because the codes can be esoteric, I would like to do something like let the user table in the ConditionName in type Icd and perform the same operation.
I believe you're asking:
Given a list of ConditionCodes, return a list of PatientIds where every patient has every condition in the list.
In that case, the easiest thing to do is group your IcdPatients table by Id, so that we can tell every condition that a patient has by looking once. Then we check that every ConditionCode we're looking for is in the group. In code, that looks like:
var result = IcdPatient.GetIcdPatientList()
// group up all the objects with the same PatientId
.GroupBy(patient => patient.PatientId)
// gather the information we care about into a single object of type {int, List<int>}
.Select(patients => new {Id = patients.Key,
Conditions = patients.Select(p => p.ConditionCode)})
// get rid of the patients without every condition
.Where(conditionsByPatient =>
conditionsByPatient.Conditions.All(condition => filteringList.Contains(condition)))
.Select(conditionsByPatient => conditionsByPatient.Id);
In query format, that looks like:
var groupedInfo = from patient in IcdPatient.GetIcdPatientList()
group patient by patient.PatientId
into patients
select new { Id = patients.Key,
Conditions = patients.Select(patient => patient.ConditionCode) };
var resultAlt = from g in groupedInfo
where g.Conditions.All(condition => filteringList.Contains(condition))
select g.Id;
Edit: If you'd also like to let your user specify the ConditionName rather than the ConditionId then simply convert from one to the other, storing the result in filteringList, like so:
var conditionNames = // some list of names from the user
var filteringList = Icd.GetIcdList().Where(icd => conditionNames.Contains(icd.ConditionName))
.Select(icd => icd.ConditionCode);