Using LINQ To Find Unique Values In A List Of Objects?
Jul 3, 2011
I am having so trouble with the ToUpper() procedure with strings. I am using LINQ to find unique values in a list of objects. In that whole process I set the values to compare to all lowercase in order to get a proper list. My goal is to populate a dropdown list with the values. I'm attempting to set the first letter of of the string to uppercase and keep the rest lowercase however the toUpper() procedure is not working?
Private Function FixCase(ByVal strIn) As String
Dim strOutput As String
Dim intStringLength As Integer = strIn.Length - 1
strOutput = strIn.Substring(0, 1)
[code].....
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May 3, 2012
I have a stored procedure (I cannot edit) that I am calling via linq.
The stored procedure returns values (more complex but important data below):
Customer Stock Item Date Price Priority Qty
--------------------------------------------------------
CUST1 TAP 01-04-2012 £30 30 1 - 30
CUST1 TAP 05-04-2012 £33 30 1 - 30
CUST1 TAP 01-04-2012 £29 20 31 - 99
CUST1 TAP 01-04-2012 £28 10 1 - 30
I am trying to limit this list to rows which have unique Dates and unique quantities in LINQ. I want to remove items with the HIGHER priority leaving rows with unique dates and qty's.
I have tried several group by's using Max and order by's but have not been able to get a result.
Is there any way to do this via linq?
EDIT:
Managed to convert brad-rem's answer into VB.net.
Syntax below if anyone needs it:
returnlist = (From p In returnlist
Order By p.Qty Ascending, p.Priority
Group By AllGrp = p.Date, p.Qty Into g = Group
Select g.First).ToList
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May 7, 2010
How can I query a DataTable to find all of the unique values in a column? SQL has the 'unique' or 'distinct' keywords, but I dont know how to do this against a DataTable.
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Dec 22, 2010
I have 2 classes
Public Class Shipper
Public Property ShipperID As Long
Public Property CreateDate As DateTime
[Code].....
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Nov 23, 2011
I'm trying to create a list of days(integer) from a list of dates(date).
I tryed to do this....
[Code]...
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Feb 24, 2009
I have a List (Of Type) which contains many instances of a class with three properties, IPAddress, AlertDate and AlertTime.There can be many duplicates of IPAddress in this list :-
[code]...
I need to be able to pull out just the latest (by date and time) entry in the list for each unique IPAddress. Is there any simple way of doing this?
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Mar 1, 2011
I have list object and I need to check id in a comma separated string using LINQ in VB.NET, something like this:
dim strId as String = "1,2,3,5,"
dim myList = from objmylist where objmylist.id in (strId)
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Oct 11, 2011
I have a list of objects, each with 2 relevant properties: "ID" and "Name". Lets call the list "lstOutcomes".I need to check the list for duplicates (meaning object1.ID = object2.ID, etc.) and set a flag (valid = false, or something) if there is at least one duplicate. Also, it would be nice to send a message to the user mentioning the "Name" of the object, when it fails.I am sure I will need to use the Group By operator to do this, but I am not used to doing that in LINQ, and the examples out there are just not helping me. This article seems to be close to what i need, but not quite and it's in C#.
Here is a starting stab at it...
Dim duplist = _
(From o As objectType In lstOutcomes _
[code]......
help?
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May 3, 2012
I have a query that 'selects' object of a type:
Dim l as IList(Of Foo) = (From dataRow As DataRow In table.Select()
Where CStr(dataRow("Column1")) = "A"
Select New Foo(CStr(dataRow("Column1")), _
CStr(dataRow("Column2")))).ToList()
What's happening is that if i set a break-point to the constructor of Foo and step, the constructor is hit and the parameters are loaded with the arguments. However, l has empty Foo objects (the members in every object are Nothing). What could be happening here?
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Jul 7, 2011
I have
Dim objectsList as List(Of Object) = GetAllObjects()
' Filter from Objects just Persons '
Dim peopleList as List(Of Person) = ???
What is the most efficient and effective LINQ expression to do it?
EDIT
1 Dim selectedObjects As List(Of Object) = GetAllObjects()
2 Dim selectedPeople As IEnumerable(Of Person)= selectedObjects.OfType(Of Person)
3 Dim people As List(Of Person) = selectedPeople.ToList()
Error on 3:
Value of type
'System.Collections.Generic.List(Of
System.Collections.Generic.IEnumerable(Of Person))' cannot be
converted to
'System.Collections.Generic.List(Of Person)'.
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Apr 27, 2012
I figure I should use 'Aggregate' but apparently I am getting it wrong First I get a list of my Entity objects Dim employers As List(Of myEntity) = (New XXXX()).getZZZ(userName, userType) Then I figured this would be a way to put all the names in a string Dim names as String = employers.Aggregate(Function(current, [next]) current.Name & " " & [next].Name)
[Code]....
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Feb 3, 2010
Basically, I am trying to write a LINQ to Objects statement where the relationship is a grandparent, parent, child relationship. (You could also call it a Master Detail relationship.)
In Legacy code here is a simplified version what I am trying to accomplish.
Dim coverages As New List(Of Coverage)
Dim coverage As Coverage
For Each rl In oClaimsPolicy.RiskLocations
coverage = New Coverage
coverage.Level = "Location"
[Code] .....
If is it not clear one Location can have many Items and one Item can have many Coverages. I basically want to list the items and show the relationship between grandparent (Location), parent (Item) and child (Coverage).
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Aug 31, 2011
I don't know if this is doable, maybe with Linq, but I have a List(Of MyType):
Public Class MyType
Property key As Char
Property description As String
End Class
And I want to create a Dictionary(Of Char, MyType) using the key field as the dictionary keys and the values in the List as the dictionary values, with something like:
New Dictionary(Of Char, MyType)(??)
Even if this is doable, internally it will loop through all the List items, I guess?
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Sep 25, 2011
Is it possible to find a complete object in list of objects?
how to find x in list1 if it exists without comparing a single property like ID ?
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Jan 10, 2009
I'm using the datagridview. This is the sample data:
[Code]....
How do I parse through the grid to rename the duplicate values in a particular column (in this example it's the l_name field) into such a format?
[Code]....
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Oct 13, 2011
I have a list of objects, each object has a score attribute,The list of scores needs to be combined on the player ID to become a totaled score or series. My current thought process is to For Each through the list of individual games, and add the score attribute to a new list of scores with the same objects. So one list would be like:
clsGame(ID Number, Sore)
dim ScoreList as list(of clsGames)
ScoreList.Add(New clsGame(11, 244)
ScoreList.Add(New clsGame(11, 333)
ScoreList.Add(New clsGame(11, 444)
Then go through combining on like ID's to make a new list of games, that would actually be the series.
Dim SeriesList as new list(of clsClasses)
For each game as clsGame in ScoreList
'cycle through the list of series seeing if an ID matches, if so add the score onto that ID
Else
[code]....
Now I don't know how to add the player if its not in the seiries list without doing a heck of a lot more for each statements. If I add it after the end if then it will be added even if it is in the list..I tried playing around with List.Contains method, but I could only see if it contaned the exact same values i.e
SeiresList.Contains(game)
and because the scores are different (series vs single game) it wouldn't match, and I don't know how to see if it contains an object with just one of the attributes the same...
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Apr 28, 2011
Im doing the same thing as him but in vb express 2008 what i have is a checklist box of 10 toppings, all of which can be selected, (no max or min) to put on a pizza, and i have 3 radio buttons grouped together for pizza size (S, M, L) i cant figure out how to give them vaules in which(for sake of demonstration) s=$5 m=$7 l=$9 and each topping is $0.25 then make them add up to an order total in a msg box or something like that
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Apr 2, 2010
I have a table with the below structure.
ID VALUE
1 3.2
2 NULL
4 NULL
5 NULL
7 NULL
10 1.8
11 NULL
12 3.2
15 4.7
17 NULL
22 NULL
24 NULL
25 NULL
27 NULL
28 7
I would like to get the max count of consecutive null values in the table.
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May 8, 2011
Unique constraint - these columns currently doesn't have unique values..?? I have created Unique Constraint with 3 columns. My code works perfectly but once - two users @ same time entered same data and somehow it saved in DB; after that incident. This UniqueConstraint gives me error - These columns currently doesn't have unique values. How can I check if user enters this kind of entry or how can I restrict the Entry?
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Aug 9, 2010
I am learning Linq, so bear with me. I have a class object that holds 4 other class objects with each holding a List(Of T) of the next. Think tiered classes. As these lists as built I need to search all the Group2 for all Group3 to see which Group3.units.count is the largest. "units" being a List(Of T). [code]
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Sep 20, 2011
For a class project I am supposed to search through the attached file, and write to a new file the years between 1789 and 2009 that are not present in the fifth field. What is my best bet for determining what years are not present?
[Code]...
Should I make an array of integer between 1789 and 2009, then search for every year in the file, then set a flag to false if not found; is there a simpler way to accomplish this using LINQ?
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Mar 10, 2012
I have a List(Of Hardware) - the List is called HWModels
Class Hardware has the following Properties:
ModelName
Status
CPUStatus
MemoryStatus
DiskStatus
The List is populated by reading a CSV file, once it's populated, I want to return the distinct records based on the ModelName
I've attempted by doing it as follows:
(From a In HWModels Select a.ModelName).Distinct
But this isn't right because I end up with a list of only the ModelName's and nothing else.
How do I get the Distinct function to return all of the other class members within the list?
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Jun 22, 2010
I have a specialized string dictionary of (string, string) (_RulesAndTheirDescriptions) that contains the name (key) and description (value) of methods in a given class. I currently do the following query to search for a match on the key or value and then bind that to a grid.
[Code]...
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Oct 1, 2010
I'm having issues with returning a list of strings of the .Value of a Linq query:
Dim details = <Details>
<Vector size="5">
<Item>Syntactic Structures</Item>
<Item>Introduction</Item>
<Item>The Independence of Grammar</Item>
[Code]...
Is correct in that it returns the list of XElements I want (items 1 - 4, base 0), but I really just need a list of strings for the .Value of those XElements. Maybe I'm just dense here, but anything I've tried in the chapterTitles query isn't working (appending with .ToList.ToString, etc.). details.<Vector>.<Item>.Skip(1).Take(4).Value just returns the first XElement's value.
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Jul 26, 2010
I have the following setup[code]...
What I would like is a Item property in the collection that I can say [code]...
I know about predicates but what I am struggling with is how to set the criteria of the predicate (i.e passing x,y,z)
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Apr 16, 2010
Having a bit of trouble using the List.Find with a custom predicate i have a function that does this
[code]...
by doing it this way means i have to have a shared "currentKey" object in the class, and i know there has to be a way to pass in the values i'm interested in of CurrentKey (namely, keyname, and oldkey) ideally i'd like to call it by something like keys.Find(AddressOf FindByOldKeyAndName(Name,OldVal))however when i do this i get compiler errors.How do i call this method and pass in the values?
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Jan 25, 2011
i've researched and written a generic class (all my objects are the same structure) and i'm was just working on the collection using a hash table but i've just read a comment within (url...) in this forum...that we shouldn't use hashtables at all with vs2008.i actually need and object collection that contains other object collections within them.the application i'm trying to write is relatively simple (but i'm new to vb.net)it keeps track of the time for weight lifting training/workouts.a workout consists of 'say' a bench press, military press, curls, dead lift, etc within the "bench" you have 1,2, or 3 sets (how many times you do "the bench", within a set you have 1,2,3 or 4 lifters, each lifter does reps.then it starts over with military press..i guess i could base it on a treeview type structure (with parent child type relationships) but i usually think in terms of collections it appears that a collectionbase has no key and i'd have to keep track of them on my own...
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Jan 29, 2011
I have a program like this.
Module Module1
Public Class Mstr
Public Property Prop1 As String
Public Property Prop2 As String[code]....
But it is not working as I expect it to. You can see it from.The DtlsB properties of all three DtlsA objects are having values from last iteration.
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Jun 12, 2012
I am building an application that contains several DataGridViews that may have 100-20,000 rows displayed with a DataTable as its DataSource.When the user wants to filter a column they right-click the DataGridView Column Header and a ContextMenuStrip shows a small DataGridView that displays all the unique values in that column. I currently get all the unique values using a loop which is slow (shown below).[code]...
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May 22, 2011
Basically i have a list(of TransRecord)
vb Public Class TransRecord
Public TableName As String
Public PKs As String
[CODE]...
And want to create a linq filter to select only unique records for TableName + PKs (group by) ... but want it to select only the record with the highest ID for this group by.
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