asked on for each where
Is there a way in vb.net select all elements from a for each statement using a where?
I am not a fan of linq for speed purposes.
It is for a game type program so speed is critical.
I want to iterate through only some elements of a list . Those elements meet some condition.
Like iterate through a list of objects where some property is set to false.
I can use a for each and and if statement currently but I am after a better way.
For Each pt In Mpl
If pt.direction = missileType Then
...
I am not a fan of linq for speed purposes.
It is for a game type program so speed is critical.
I want to iterate through only some elements of a list . Those elements meet some condition.
Like iterate through a list of objects where some property is set to false.
I can use a for each and and if statement currently but I am after a better way.
For Each pt In Mpl
If pt.direction = missileType Then
...
Visual Basic.NET.NET ProgrammingC#
Last Comment
Gururaj Badam
The only way to do that is with LINQ. Dim pts = From pt In Mpl Where pt.Direction = missleType For Each pt In pts '''' NextWayne
You can use the List.FindAll() method:
http://msdn.microsoft.com/en-us/library/fh1w7y8z.aspx
Really not sure if it is "better" though...just different...
Made up example:
http://msdn.microsoft.com/en-us/library/fh1w7y8z.aspx
Really not sure if it is "better" though...just different...
Made up example:
Public Class Form1
Private Const missileType As Integer = 0
Private Class Something
Public direction As Integer
End Class
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim Mpl As New List(Of Something)
' ...
For Each pt In Mpl.FindAll(AddressOf FindMissiles)
' ...
Next
End Sub
Private Function FindMissiles(ByVal pt As Something) As Boolean
Return pt.direction = missileType
' ... obviously a more complicted match algorithm could be used in here! ...
End Function
End Class
what about creating a dynamic datatable, put elements into it (maybe you already getting values from db, in this case you may have a datatable already)
then you can use rowfilter property of datatable.defaultview.rowf
--> http://msdn.microsoft.com/en-us/library/system.data.dataview.rowfilter.aspx
then you can use rowfilter property of datatable.defaultview.rowf
--> http://msdn.microsoft.com/en-us/library/system.data.dataview.rowfilter.aspx
ASKER
thanks for the replies.
actually it looks worse with all these extra functions and I am wooried about speed as well, database no way and MSDN examples dont always clarify things. Who wites MSDN stuff and does it get proof read for simplicity?
actually it looks worse with all these extra functions and I am wooried about speed as well, database no way and MSDN examples dont always clarify things. Who wites MSDN stuff and does it get proof read for simplicity?
I'm a C# guy, pardon my syntax.
For Each pt In Mpl.Where pt => pt.direction = missileType
this will only iterate elements matching your where condition. I don't know why you feel LINQ will slow down your processing when it's actually design gain performance.
For Each pt In Mpl.Where pt => pt.direction = missileType
this will only iterate elements matching your where condition. I don't know why you feel LINQ will slow down your processing when it's actually design gain performance.
ASKER
i havent read anywhere Liunq speeds up performance and have only heard it slows things down because of its design.
Could you show me any article where it says iterating through a list of data using linq is quicker ( or no slwere)than using an if condition .
Could you show me any article where it says iterating through a list of data using linq is quicker ( or no slwere)than using an if condition .
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