I have a for loop that is working as intended. I iterate over an array of values and replace bad values (-99999) with the closest good value (if the bad value is on either end of the array) or the average of the two surrounding values (if the bad value is in the middle of the array). However, these nested loops smelled to me and I am looking for any suggested means of optimizing this (in terms of readability or performance).
I could access or remove the bad values using Dim badValues = MeasuredValues.Where(Function(x) x = -99999) but I'm not sure how I can keep track of the indexes for calculating the replacement value when using .Where. I'm no vb.net expert.
For index = 0 To MeasuredValues.Count - 1
If MeasuredValues(index) = -99999 Then
Dim nextGoodValue = -99999
Dim previousGoodValue = -99999
Dim replacementValue = -99999
For j = index To MeasuredValues.Count - 1
If MeasuredValues(j) <> -99999 Then
nextGoodValue = MeasuredValues(j)
Exit For
End If
Next
For k = index To 0 Step -1
If MeasuredValues(k) <> -99999 Then
previousGoodValue = MeasuredValues(k)
Exit For
End If
Next
If previousGoodValue = -99999 Then
replacementValue = nextGoodValue
ElseIf nextGoodValue = -99999 Then
replacementValue = previousGoodValue
Else
replacementValue = (nextGoodValue + previousGoodValue) / 2
End If
MeasuredValues(index) = replacementValue
End If
Next
Thanks for your time, please let me know if you need more info or have any questions.
Related
Good morning,
I have a problem with the for-next loop. At the second iteration of the cycle, the exit from the cycle occurs even if the exit condition on variable j is not respected. I would have solved the problem with the goTo statement. However I am wondering why index reset does not work in this case.
Thank you.
For j = LBound(AttivitaTemp) To UBound(AttivitaTemp)
If confronta(AttivitaTemp(j), AttivitaFinali) = "#N/D" Then
activityTemp = AttivitaTemp(j)
rigaTemp = confronta(activityTemp, Attivita)
SuccessioniTemp = estrai_riga(MatriceElenchiSuccessioni, rigaTemp)
SuccessioniTemp = cancella_vuoti_vettore(SuccessioniTemp)
ESsuccessioni = EF(rigaTemp)
For k = LBound(SuccessioniTemp) To UBound(SuccessioniTemp)
rigaTemp = confronta(SuccessioniTemp(k), Attivita)
ES(rigaTemp) = Application.WorksheetFunction.Max(ES(rigaTemp), ESsuccessioni)
EF(rigaTemp) = ES(rigaTemp) + Durate(rigaTemp)
Next
VettoreSuccessioniTemp = unisci_vettori(VettoreSuccessioniTemp, SuccessioniTemp)
If j = UBound(AttivitaTemp) Then
AttivitaTemp = VettoreSuccessioniTemp
ReDim VettoreSuccessioniTemp(0)
j = LBound(AttivitaTemp) - 1
'GoTo ricomincia_ciclo_j
End If
End If
Next
Observing the variable j at the second iteration it results j = 0, with the next it goes to j = 1 but the for loop is not re-executed, although UBound (AttivitaTemp) is equal to 1.
In other words, why does this simple cycle work instead, which conceptually does the same thing?
For x = 0 To 2
If x = 2 Then
x = -1
End If
Next
I solved it by myself: the problem is that even if it is possible to reset the iterator, it is not possible to update the conditions of the for loop (the values of "from" and "to" remain "frozen" even if during the loop they are changed).
so I thought this would be a simple logical problem, but for the life of me I cannot find the issue with this code block. I have checked around on Stack for a solution, but all other do/while loop problems appear to be primarily with other languages.
What I am trying to do is simply loop through an array & add a new worksheet for each element in the array that is not null. Pretty simple right? Yet for some reason it simply loops through once and thats it.
Here is the code block:
Dim repNames() As String
Dim x As Integer
x = 25
ReDim repNames(1 To x)
repNames(1) = "Ahern"
repNames(2) = "Castronovo"
repNames(3) = "Glick"
repNames(4) = "Fields"
repNames(5) = "Murphy"
repNames(6) = "Sleeter"
repNames(7) = "Vivian"
repNames(8) = "Walschot"
repNames(9) = "Wilson"
Dim i As Integer
i = 1
Do 'Loop keeps creating only 1 new sheet. Should create 9.
Worksheets.Add.Name = repNames(i)
i = i + 2
Loop While repNames(i) <> Null
I believe the problem is with this line: Loop While repNames(i) <> Null,
but obviously the logical test seems to hold up.
Any help would be hugely appreciated!
As others note, Null is not the comparison you want to make. Testing anything for equivalence with Null will return Null -- even ?Null = Null returns Null, which is why your loop is exiting early. (Note: To test for a Null, you need to use the IsNull function which returns a boolean, but that is NOT how you test for an empty string.)
In VBA, to test for a zero-length string or empty string, you can use either "" or vbNullString constant, or some people use the Len function to check for zero-length.
Rectifying that error, as originally written in your code, your logical test should abort the loop if any item is an empty string, but none of the items are empty strings (at least not in the example data you've provided) so you end up with an infinite loop which will error once i exceeds the number of items in the repNames array.
This would be probably better suited as a For Each loop.
Dim rep as Variant
For Each rep in repNames
Worksheets.Add.Name = rep
Next
If you need to skip empty values, or duplicate values, you can add that logic as needed within the loop:
For Each rep in repNames
If rep <> vbNullString 'only process non-zero-length strings
Worksheets.Add.name = rep
End If
Next
Etc.
Firstly, you should be comparing to vbNullString. This loops multiple times:
' Declare variables
Dim repNames() As String
Dim x As Integer
Dim i As Integer
' Set data
x = 25
ReDim repNames(1 To x)
repNames(1) = "Ahern"
repNames(2) = "Castronovo"
repNames(3) = "Glick"
repNames(4) = "Fields"
repNames(5) = "Murphy"
repNames(6) = "Sleeter"
repNames(7) = "Vivian"
repNames(8) = "Walschot"
repNames(9) = "Wilson"
' Loop through items
i = 1
Do
Worksheets.Add.Name = repNames(i)
i = i + 2
Loop While repNames(i) <> vbNullString
There is one more problem – why i = i + 2 ? In your question you say you wanted the loop to execute 9 times, but using i = i + 2 skips every other item. If you indeed want to loop through every item:
Do
Worksheets.Add.Name = repNames(i)
i = i + 1
Loop While repNames(i) <> vbNullString
Here you go, I have changed the loop conditional, and changed i=i+2 to i=i+1. A regular while loop would be better than a do while encase the first element is empty
Dim repNames()
Dim x As Integer
x = 25
ReDim repNames(1 To x)
repNames(1) = "Ahern"
repNames(2) = "Castronovo"
repNames(3) = "Glick"
repNames(4) = "Fields"
repNames(5) = "Murphy"
repNames(6) = "Sleeter"
repNames(7) = "Vivian"
repNames(8) = "Walschot"
repNames(9) = "Wilson"
Dim i As Integer
i = 1
Do While repNames(i) <> ""
Worksheets.Add.Name = repNames(i)
i = i + 1
Loop
I Have about 10 (DatagridView Count may varies As per User Selected Files From 2 to 10) Datagridview ,So How can i find common value from all Datagridviews ??
Comment If you need more brief details
Below is mine but It find common from 2 -2 datagridviews
For i As Integer = 1 To dgvCont
For j As Integer = 0 To Main.DGVM(i).Rows.Count - 1
For Each Val As DataGridViewRow In Main.DGVM(i + 1).Rows
If Val.Cells(0).Value = Main.DGVM(i).Rows.Item(j).Cells(0).Value Then
Dim cm As String = Val.Cells(0).Value
If cm = "" Then
Else
Analysis.lvCmn.Items.Add(Val.Cells(0).Value)
End If
End If
Next
Next
Next
I understand that you want to set two nested loops accounting for an undetermined number of elements (items in an array of DataGridView, I presume), performing the checks you want:
For count1 As Integer = 1 To dgvCont 'Assuming indices from 1 to dgvCont
For row1 As Integer = 0 To Main.DGVM(count1).Rows.Count - 1
If (Main.DGVM(count1).Rows(row1).Cells(0).Value Is Nothing) Then Continue For
Dim val1 As String = Main.DGVM(count1).Rows(row1).Cells(0).Value
Dim found As Boolean = False
For count2 As Integer = 1 To dgvCont 'Assuming indices from 1 to dgvCont
If (count2 = count1) Then Continue For
For row2 As Integer = 0 To Main.DGVM(count2).Rows.Count - 1
If (Main.DGVM(count2).Rows(row2).Cells(0).Value Is Nothing) Then Continue For
Dim val2 As String = Main.DGVM(count2).Rows(row2).Cells(0).Value.ToString()
If val1 = val2 Then
Dim cm As String = val1
If cm = "" Then
Else
Analysis.lvCmn.Items.Add(val1)
End If
found = True
Exit For 'By assuming that you want to stop searching after finding a match
End If
Next
If (found) Then Exit For 'By assuming that you want to stop searching after finding a match
Next
Next
Next
Your code is not too clear (neither what you want); but this should give you a good enough start to carry out the implementation you are looking for. Bear in mind that this code (like yours) only considers one column (first one); in case of wanting to iterate through all the columns, you would have to add further nested loops accounting for that.
This code generates a stack overflow. I'm aware it is caused by the procedure calling itself.
What can I do to avoid the stack overflow? Recalling the sub procedure and generating a new random number is the easiest thing to do, however it generates the overflow. The randomly generated number picks a random inventory item, then the if statement matches that number (random inventory item) with the quantity of that item from the deck inventory to make sure it isn't less than 1. If the inventory of that item is 0, the else plays and restarts the procedure, generating a new random number and doing the process all over again. In another procedure I have a function that if the deck's inventory becomes completely empty, then the discard pile replenishes the deck, making the discard pile empty, so there should never be a case where all randomly generated numbers can be associated item with a inventory of 0.
I wonder if I could somehow force the random number generator
Number = (DeckGroup(Rnd.Next(0, DeckGroup.Count)).ID)
not to generate numbers to inventory items DeckGroup(Number).QuantityInteger that are zero. By doing so I wouldn't even need to recall the function.
The random number is generated by a different branch in the same structure group.
Private Sub PlayElse()
Dim CardCheckBoxArray() As CheckBox = {CardCheckBox1, CardCheckBox2, CardCheckBox3, CardCheckBox4, CardCheckBox5}
'Reset Number Generator
Number = (DeckGroup(Rnd.Next(0, DeckGroup.Count)).ID)
Dim PlayerQuantitySubtractionInteger As Integer
For PlayerQuantitySubtractionInteger = ChecksDynamicA To ChecksDynamicB
If CardCheckBoxArray(TextBoxInteger).Checked = True And DeckGroup(Number).QuantityInteger > 0 Then
DeckGroup(Number).QuantityInteger -= 1
'Select the Player depending value of T
Select Case T
Case 0
Player1HandGroup(Number).QuantityInteger += 1
Case 1
Player1HandGroup(Number).QuantityInteger2 += 1
Case 2
Player1HandGroup(Number).QuantityInteger3 += 1
Case 3
Player1HandGroup(Number).QuantityInteger4 += 1
Case 4
Player1HandGroup(Number).QuantityInteger5 += 1
End Select
CardTypeArray(PlayerQuantitySubtractionInteger) = Player1HandGroup(Number).CardType
CardCheckBoxArray(TextBoxInteger).Text = Player1HandGroup(Number).CardNameString
NumberArray(PlayerQuantitySubtractionInteger) = Number
Else
If CardCheckBoxArray(TextBoxInteger).Checked = True And DeckGroup(Number).QuantityInteger < 0 Then
Call PlayElse()
End If
End If
Next PlayerQuantitySubtractionInteger
End Sub
You could use LINQ to weed out all the objects you never want to get first and then use the collection returned by the linq instead of your original collection.
Something like:
Private Sub PlayElse()
Dim CardCheckBoxArray() As CheckBox = {CardCheckBox1, CardCheckBox2, CardCheckBox3, CardCheckBox4, CardCheckBox5}
'Reset Number Generator
Dim temp As IEnumerable(Of LunchMoneyGame.LunchMoneyMainForm.Group) = From r In DeckGroup Where r.QuantityInteger > 0 Select r
If temp IsNot Nothing AndAlso temp.Any Then
Number = (temp(Rnd.Next(0, temp.Count)).ID)
' ** Edit **: This will ensure that you only got 1 object back from the LINQ which can tell you whether or not you have bad data. You *can* exclude this check but its good practice to include it.
Dim obj As LunchMoneyGame.LunchMoneyMainForm.Group = Nothing
Dim t = From r In temp Where r.ID = Number Select r
If t IsNot Nothing AndAlso t.Count = 1 Then
obj = t(0)
End If
If obj IsNot Nothing Then
Dim PlayerQuantitySubtractionInteger As Integer
For PlayerQuantitySubtractionInteger = ChecksDynamicA To ChecksDynamicB
' ** Edit **
obj.QuantityInteger -= 1
'Select the Player depending value of T
Select Case T
Case 0
Player1HandGroup(Number).QuantityInteger += 1
Case 1
Player1HandGroup(Number).QuantityInteger2 += 1
Case 2
Player1HandGroup(Number).QuantityInteger3 += 1
Case 3
Player1HandGroup(Number).QuantityInteger4 += 1
Case 4
Player1HandGroup(Number).QuantityInteger5 += 1
End Select
CardTypeArray(PlayerQuantitySubtractionInteger) = Player1HandGroup(Number).CardType
CardCheckBoxArray(TextBoxInteger).Text = Player1HandGroup(Number).CardNameString
NumberArray(PlayerQuantitySubtractionInteger) = Number
Next PlayerQuantitySubtractionInteger
End If
End If
End Sub
Pass through the list and determine only those that are valid. Then randomly pull from that set. Here is a simple version of it. You could use LINQ as well, but this should be clear enough:
Dim validDeckGroupsIndexes As New List(Of Integer)
For ndx As Integer = 0 to DeckGroup.Count - 1
If DeckGroup(ndx).QuantityInteger > 0 Then
validDeckGroupsIndexes .Add(ndx)
End If
Next ndx
Then use this:
Dim deckGroupNdx As Integer = Rnd.Next(0, validDeckGroupsIndexes.Count)
Number = DeckGroup(deckGroupNdx).ID
In this datatable there are no duplicates, I need the row index where column x value equals 2. I would do it like this:
Dim rowIndex As Integer = 0
For i = 0 To mtable.Rows.Count - 1
If mtable.Rows(i)("x") = 2 Then
rowIndex = i
Exit For
End If
Next
I will be calling this process multiple times per second. Is there a faster way to do this in .NET?
DataTable select could work, i think it should be faster than iterating over the collection of rows.
var index = mtable.Rows.IndexOf(mtable.Select("x = 2").FirstOrDefault());
Multiple times per second is a bit vague - tens or thousands?
You could create a hash table mapping the value of "x" to the row number:
Dim nLookups = mtable.Rows.Count - 1
Dim lookupHash As New Hashtable(nLookups)
For i = 0 To nLookups
lookupHash.Add(CInt(mtable.Rows(i)("x")), i)
Next
then
Dim rowSought As Integer = -1
If lookupHash.ContainsKey(2) Then
rowSought = lookupHash(2)
End If
Or if the range of possible values of "x" is suitable, you could use an array to map the value to the row number.