I have a dynamic array ,where the array size changes according to the no.of rows in database
code goes like this :
Dim pgm_act_arr(0) As Double
Dim pgm_act_count As Integer = no.of rows retuned from database
ReDim pgm_act_arr(pgm_act_count)
for each rows in database1
'i want to reinitialize the array here
'now am using for loop to reinitialize array to zero
For i As double to pgm_act_arr.Length
pgm_act_arr(i) = 0.0
Next
for each rows in database2
pgm_act_arr(index)+=somevalue 'inserting values to array elements
next
next
Is there any single line code or any short hand operations to reinitialise the array
Not entirely sure i have understood the Q but....
Not sure if it is the right way but i always redim as i go so code would look like this:
Dim pgm_act_arr(0) As Double
for each rows in database2
pgm_act_arr(index)+=somevalue 'inserting values to array elements
ReDim preserve pgm_act_arr(ubound(pgm_act_arr)+1)
next
'remove blank entry at bottom
ReDim preserve pgm_act_arr(ubound(pgm_act_arr)-1)
To reset the array to as it started
ReDim pgm_act_arr(0)
So consider array size as 3
i.e.
pgm_act_arr(0)=1
pgm_act_arr(1)=2
pgm_act_arr(2)=3
so what i want to do is
pgm_act_arr(0)=0
pgm_act_arr(1)=0
pgm_act_arr(2)=0
But as far as i know this is the simplest way
for i=0 to 2
pgm_act_arr(i)=0.0
next
Related
Hello I have two dimensional array as below in LotusScript.
Counter = 0
While Not (ProcessingViewDoc Is Nothing )
Redim Preserve AllRecrods(Counter,0)
AllRecrods(Counter,0) = ProcessingViewDoc.Test1(0)
Redim Preserve AllRecrods(Counter,1)
AllRecrods(Counter,1) = ProcessingViewDoc.Test2(0)
Redim Preserve AllRecrods(Counter,2)
Set ProcessingViewDoc = ProcessingView.GetNextDocument(ProcessingViewDoc)
Counter = Counter +1
Wend
When It processes next document it does and reaches to counter 1 and second document it gives me error subscription out of range.
Here is global declaration of array.
Dim AllRecrods() As Variant
Here is the line when it gives error when it goes to loop second time.
Redim Preserve AllRecrods(Counter,0)
In addition to Richard's excellent answer, I would suggest a couple of things.
1) Instead of While Not (ProcessingViewDoc Is Nothing) (which contains two negatives, making it harder to read), use Do Until doc Is Nothing. It is much clearer.
2) If you use a list, you don't have to worry about redim of the array. You could make it a list of a custom data type, and if you use the UNID of the document as the key, you can quickly connect the values back to the originating document.
My code would look something like this:
--- Declarations ---
Type recordData
value1 As String
value2 As String
End Type
--- Main Code ---
Dim allRecords List As recordData
Dim unid as String
Do Until ProcessingViewDoc Is Nothing
unid = ProcessingViewDoc.UniqueID
allRecords(unid).value1 = ProcessingViewDoc.Test1(0)
allRecords(unid).value2 = ProcessingViewDoc.Test2(0)
Set ProcessingViewDoc = ProcessingView.GetNextDocument(ProcessingViewDoc)
Loop
You are using ReDim with the Preserve option and changing both of the dimensions. You can't do that.
From the documentation for the ReDim statement:
If Preserve is specified, you can change only the upper bound of the
last array dimension. Attempting to change any other bound results in
an error.
Also, the logic there is screwed up. You're doing three redims on every iteration, with the first one shrinking the second dimension back to zero on every iteration. Even if you weren't changing the first dimension, that would lose the data that you stored in AllRecrods( n ,1) because the preserve option can't keep data in a dimension that you shrink below the size that you've already used!
You should probably consider swapping your two dimensions, reversing them in your assignments, keeping the first dimension constant at 2, and eliminating two of your ReDim Preserve statements. I.e., just do one ReDim Preserve AllRecrods(2,counter) on each iteration of the loop.
I have a set of data where each item has a 2D array of information corresponding to it. I'd like to create a 3D array where the first dimension is the item name and the second and third dimensions are taken up by the info corresponding to the item.
I can read the data for each item into a 2D array, but I can't figure out how to get the 2D array read into the 3D array.
I know the sizes of all the dimensions so I can create an array of fixed size before I begin the reading and writing process.
I'd like to do this by looping only through the names of the items and not looping through every cell of every 2D array.
It is easy to get the 2D arrays read in to an ArrayList but I want to be able to name the items and be able to read these back in to excel and it seems difficult to do with an ArrayList.
The question is: how do I read a 2D selection from excel into a 3D fixed sized array in VBA?
Here is an example of each approach: array of arrays or Dictionary of arrays. The Dictionary approach is considerably easier than the array of arrays if what you want is keyed lookup of values. There might be merits to the array of arrays in other cases.
This is dummy code with no real purpose but to show a couple things: grabbing a single value and an array of values. I am building a 2D array of values by grabbing some Range data which is easy and 2D. From there I build up the arrays of these values and then put them into the relevant data structure. Then I poke at the data structure to get some values out of it.
Array of Arrays approach is shown first (and outputs on the left of the picture).
Sub ArraysOfArrays()
Dim arrA() As Variant
Dim arrB() As Variant
'wire up a 2-D array
arrA = Range("B2:D4").Value
arrB = Range("F2:H4").Value
Dim arrCombo() As Variant
ReDim arrCombo(2, 1) As Variant
'name and give data
arrCombo(0, 0) = "arrA"
arrCombo(1, 0) = arrA
'add more elements
ReDim Preserve arrCombo(2, 2)
arrCombo(0, 1) = "arrB"
arrCombo(1, 1) = arrB
'output a single result
'cell(2,2) of arrA
Range("B6") = arrCombo(1, 0)(2, 2)
Dim str_search As String
str_search = "arrB"
'iterate through and output arrB to cells
Dim i As Integer
For i = LBound(arrCombo, 1) To UBound(arrCombo, 1)
If arrCombo(0, i) = str_search Then
Range("B8").Resize(3, 3).Value = arrCombo(1, i)
End If
Next i
End Sub
Couple key points here:
You can only expand the array using ReDim. ReDim is very particular that you only change the last dimension of the array when used with Preserve. Since I need one of them to track the number of entries, I do that in the second index which is... unnatural. If you know the size in advance, this painful step is skipped.
My final array is a 2xN array where the 2 contains a name and a YxZ array of data.
In order to find a given array in the mix, you have to iterate through them all.
Dictionary of Arrays is far less code and more elegant. Be sure to add the reference Tools->References in the VBA editor to Microsoft Scripting Runtime.
Sub DictionaryOfArrays()
Dim dict As New Scripting.Dictionary
'wire up a 2-D array
arrA = Range("B2:D4").Value
arrB = Range("F2:H4").Value
dict.Add "arrA", arrA
dict.Add "arrB", arrB
'get a single value
Range("F6") = dict("arrB")(2, 2)
'get a array of values
Range("F8").Resize(3, 3) = dict("arrA")
End Sub
Picture of input data and results
Data to copy if you want it (paste in B1)
a b
1 2 3 10 11 12
4 5 6 13 14 15
7 8 9 16 17 18
I am curious if I can copy multiple columns to a new array from an existing array in one iteration of a loop. Suppose we have the following general example:
Array1 contains 10,000 elements in column1, 10,000 elements in column2, and 10,000 elements in column 3, etc.
Let's say that I want a new array generated off that information, only I want only columns 1 and 2 populated. Can I do this by looping only once with a correctly dimensioned target array? For instance:
'Assume TargetArray has already been ReDimmed to the size of Array1 in the code prior
For i=0 to UBound(Array1)
TargetArray(x,1)= Array1(x,1)
TargetArray(x,2)=Array1(x,2)
Next
So can this be done in one step, or do I have to make a loop for each dimension I want to add to the array. Is there any speed savings by doing two operations per loop as stated above (assuming it works).
Thanks for all of your help!
Have you tried just using Range objects? I just made 100 values in columns A and B, and copy them to F and G. Or are you trying to plug values from the first three columns into an equation to give you values for the new two columns?
Sub CopyRange()
Dim Array1 As Range
Dim Array2 As Range
Set Array1 = Range("A1:B100")
Set Array2 = Range("F1:G100")
Array2.Value = Array1.Value
End Sub
Your example should work as what RubberDuck commented.
It is similar in below example which works at my end.
I can't fit it to comments so I have no choice to post it as answer.
Dim TargetArray ' declared as Variant type, not array of variants
ReDim TargetArray(0 To Ubound(Array1, 0), 0 To 1) ' for 2 columns
For i = 0 To Ubound(Array1, 1)
TargetArray(i, 0) = Array1(i, 0)
TargetArray(i, 1) = Array1(i, 1)
Next
Is this close to what you have? If so, then that should work.
I have a first row with 100 cells and I created an Array of Strings, which represent the new row content.
I would like to replace the content of all the first row with the content of my Array in VBA, how can I do that?
Say your array is called myArray, it's enough to do this:
For j = LBound(myArray) To UBound(myArray)
Sheets("your sheet").Cells(1,j+1).Value = myArray(j)
Next j
The functions LBound() and UBound() are respectively returning the first and the last index of your array.
Please note that when writing Cells(1,j+1) I'm assuming two important things:
1) Your start index starts with 0, so I want to start the insertion of the values from the column 1 (j+1 = 0+1 = 1).
2) You want to override the first row (because the row index is equal to 1).
You might want to customize this, for example creating independent indexes - when I say "independent", I mean "not depending on the lower and the upper bound of your array, nor being hard-coded like I did for the "row 1".
You can read and write between a Range and an Array in one line. It is more efficient than using a loop.
Note: The array must be 2 Dimensional to write to a range.
Public Sub ReadToArray()
' Create dynamic array
Dim StudentMarks() As Variant
' Read values into array from 100 cells in row 1
StudentMarks = Sheets("Sheet1").Range("A1:CV1").Value
' Do something with array
' Write the values back to sheet
Sheets("Sheet1").Range("A1:CV1").Value = StudentMarks
End Sub
In VBA is it possible to loop through, for example, every column of a 2 dimensional array and perform and operation on each column? I would like to pass each column or row of an array sequentially to a function.
Thanks.
Normally I'd not answer this because you haven't shown any effort in trying.. But I've had my own difficulty with this (with my own question currently posted looking for a better solution) and I'm bored so:
if you have a 2D array named myArr like this:
1,2,3,4,5
6,7,8,9,10
11,12,13,14,15
defined by: dim myArr(2,4) as variant
then you could loop through it with a double loop like this:
For i = LBound(myArr) To UBound(myArr)
For j = LBound(myArr, 2) To UBound(myArr, 2)
temp(j) = myArr(i, j)
Next
Next
where temp is defined and reDim'd like this:
dim temp() as variant
redim temp(lbound(myArr,2), ubound(myArr,2)) 'note the ",2" gets the bounds of the 2nd dimention
and then pass temp to a function: FunctionName(Temp)
So put that together by sticking thue function call after the inner loop and it would loop through and pass temp to the function for each row