Use math equation input value to do math calculation in VBA Exccel - vba

I'm doing numerical integration in Excel VBA and I want to get the equation from the user instead of inserting it in the Cell.
Example
The user gives me x^3+x^2+2 which is F(X)
In A1, I have number 2 and I evaluate F(X) in B1.
How to tell excel that the equation input from user is =A1^3+A2^2+2. I just need that conversion to one cell.
I'm using Val(InputBox())
Thanks for the help

If the user enters x or X and you only need to replace X with A1.cell.value then use this:
Sub test()
formula_user = InputBox("Please type formula")
Range("B1").Formula = "=" & Replace(LCase(formula_user), "x", "A1")
End Sub
x is replace with A1 in the formula from the user inputbox. It can be upper or lower case in the user input

The Application Evaluate function can resolve the formula received from the user but you will have to find someway to convert x to a cell reference that can be correctly understood. This may require the worksheet name.
Your x^3+x^2+2 example replaces two x values with A1 and A2. It may be better as x^3+y^2+2 so that there is no ambiguity between what is A1 and what is A2.
Sub f_of_x_and_y()
Dim fmla As String, str As String
fmla = InputBox("enter formula")
With Worksheets("Sheet2")
str = Replace(Replace(fmla, "x", .Range("A1").Address(external:=True)), _
"y", .Range("A2").Address(external:=True))
.Range("A3") = Application.Evaluate(str)
End With
End Sub

Sub variable_input()
Dim userFormula$
Dim myVar&
myVar = 2
userFormula = InputBox("What is the formula?")
Debug.Print userFormula
userFormula = Replace(userFormula, "x", myVar)
Debug.Print userFormula
Dim theAnswer$
theAnswer = Val(userFormula)
Debug.Print theAnswer
End Sub

You can replace all "x" with the string "A1". Don't forget to add "=" in front...
Sub TestUserEquation()
Dim strUserEquation As String
strUserEquation = LCase(InputBox("Please enter your equation:", "Equation InputBox"))
If strUserEquation <> "" Then
Cells(1, 2) = "=" & Replace(strUserEquation, "x", "A1")
Else
Cells(1, 2) = "No equation entered."
End If
End Sub

Related

Assign value to a range with a variable column refreence

The following code gives me a compile error:expected: separator or ).
Public Sub test1()
Dim first_column As String,a_tab as string
a_tab="Sheet1"
first_column = "A"
ThisWorkbook.Sheets(a_tab).Range(first_column&"10").value="hello"
End Sub
I know we can do it when the row reference is a variable, i.e.
Public Sub test1()
dim fist_row as integer, a_tab as string
a_tab="Sheet1"
first_row=10
ThisWorkbook.Sheets(a_tab).Range("A"&first_row).value="hello"
End Sub
Could someone help? Many thanks.
Get out of the habit of using a letter for the column designation.
Your first column is column 1:
Columns(1).Value = "Hello" will place "Hello" in every cell in column 1 - Range(A1:A1048576).
The second cell in column 1:
Cells(2, 1) = "Hello" will place "Hello" in row 2, column 1 - Range(A2).
A range of cells designated by a start and end cell:
Range(Cells(2, 1), Cells(4, 2)) = "Hello" will place "Hello" in every cell between row 2, column 1 and row 4, column 2 - Range("A2:B4")
The first, second, third & fourth columns:
Range(Cells(1,1),Cells(1,4)).EntireColumn - Range("A:D").
But, saying that the only thing that caused your code to fail was spacing. You'll notice with the row variable it keeps putting the spaces back in - doesn't seem to do that with the column variable:
ThisWorkbook.Sheets(a_tab).Range(first_column & "10").Value = "hello"
- add a space either side of the ampersand.
Edit:
Consider placing values in columns CB:CL using a loop. Using numbers you'd just write:
Sub Test()
Dim x As Long
For x = 80 To 90
Cells(1, x) = "Hello"
Next x
End Sub
Using letters you'd have to use something like:
Sub Test()
Dim col_Letter As String
col_Letter = "CB"
Do
Range(col_Letter & "10") = "Hello"
'Get the next column letter by finding the address, splitting it and extracting just the column letter.
col_Letter = Split(Range(col_Letter & "10").Offset(, 1).Address(True, False), "$")(0)
Loop While col_Letter <> "CL"
End Sub
Are you missing spaces when concatenating strings in your argument to Range? ThisWorkbook.Sheets(a_tab).Range(first_column & "10").value="hello" Works for me if I add the spaces.

Excel conversion of text containing ranges--numeric to alpha-numeric

I would like to convert a range of numbers (and single digits) from a number-only format to alpha-numeric format. Entire statement is in a single, excel cell and would like the converted version to be in a neighboring cell.
As an example:
Assuming 1-24=B1-B24
Assuming 25-48=C1-C24
INPUT—
screen 1-3,5,7-9,11-30,32-37,39-40,41,44-46
DESIRED OUTPUT (all acceptable)
screen B1-B3,B5,B7-B9,B11-C6,C8-C13,C15-C16,C17,C20-C22
OR
screen B1-B3,B5,B7-B9,B11-B24,C1-C6,C8-C13,C15-C16,C17,C20-C22
OR
screen B1-B3,B5,B7-B9,B11-B24
screen C1-C6,C8-C13,C15-C16,C17,C20-C22
Using excel functions is proving quite cumbersome so excel macro would be better. I've looked for examples of requested conversion but haven't found anything.
Any help is greatly appreciated.
Cheers,
Bob
Hey here is a solution that i tested out. Not sure if "screen" needs to be in the string or not. Let me know and I will tweak it if that's the case.
Its a user defined function. So drop this vba in a module and then go to a worksheet and type in "=AlphaConvert(" + the cell reference.
Assumption here is that only one cell will be referenced at a time.
Last this could easily be converted to a sub routine and probably run a bit faster than the function.
Public Function AlphaConvert(TargetCell As Range)
Dim v As Long
Dim vArr() As String
Dim i As Long
Dim iArr() As String
Dim a As String
vArr = Split(TargetCell.Value, ",")
For v = LBound(vArr) To UBound(vArr)
If InStr(vArr(v), "-") > 0 Then
iArr = Split(vArr(v), "-")
For i = LBound(iArr) To UBound(iArr)
If i = LBound(iArr) Then
a = AlphaCode(iArr(i))
Else
a = a & "-" & AlphaCode(iArr(i))
End If
Next i
vArr(v) = a
Else
vArr(v) = AlphaCode(vArr(v))
End If
If v = LBound(vArr) Then
AlphaConvert = vArr(v)
Else
AlphaConvert = AlphaConvert & "," & vArr(v)
End If
Next v
End Function
Private Function AlphaCode(Nbr As Variant)
Select Case Nbr
Case 1 To 24
AlphaCode = "B" & Nbr
Case Else
AlphaCode = "C" & Nbr - 24
End Select
End Function

How do I check whether value in active cell contains any letter or not?

For example cell "A1" is linked to cell "B1", so in formula bar for cell "A1" we have:
=B1
How can I check whether value in cell "A1" contains letter B?
I tried the following:
Dim Criteria_3 As Boolean
Dim Value As Range
Set Value = Selection
Dim x As Variant
Set x = Cells
Dim text As String
For Each x In Value
If IsNumeric(x) Then
Criteria_3 = VBA.InStr(1, x.Formula, text) > 0
As soon as value of "Text" is "" it does not work and I really struggle to fined the right solution.
your question is not really conclusive, so here are two options:
To check wheter the value contains B:
blnCheck = 0 < InStr(1, rngCell.Value, "B")
To check wheter the Formula contains B:
blnCheck = 0 < InStr(1, rngCell.Formula, "B")
Regarding your null string problem:
As soon as value of "Text" is "" it does not work and I really struggle to fined the right solution.
That's because you're using VBA.InStr(1, x.Formula, text) and in this case 1 is an invalid index on a string of length 0. You can omit that, or you can code around it like:
If Len(Trim(x.Formula)) = 0 Then
'## Do nothing
Else
Criteria_3 = VBA.InStr(1, x.Formula, text) > 0
End If
To your specific question of identifying when a value contains any alpha character(s):
You can use a function like this to test whether a value contains any letter, by evaluating the Ascii code for each character, and break when True:
Function ContainsAnyLetter(val) As Boolean
Dim ret As Boolean
Dim str$, ch$
Dim i As Long
str = LCase(CStr(val))
For i = 1 To Len(str)
ch = Mid(str, i, 1)
If 97 <= Asc(ch) And Asc(ch) <= 122 Then
ret = True
Exit For
End If
Next
ContainsAnyLetter = ret
End Function
In your code, you could call it like:
Criteria_3 = ContainsAnyLetter(x.Value) '## or x.Formula, depending on your needs
You can use LIKE
https://msdn.microsoft.com/en-us/library/swf8kaxw.aspx
Something like if rngCell.value like "*B*" then
if your goal is to check whether the cell contains any valid range reference, then you could go like this
Option Explicit
Sub main()
Dim cell As Range
For Each cell In Worksheets("Sheet001").Range("A1:A20") '<== jus a test range, set it as per your needs
MsgBox IsCellReference(cell.Formula)
Next cell
End Sub
Function IsCellReference(text As String) As Boolean
On Error Resume Next
IsCellReference = Not Range(Replace(text, "=", "")) Is Nothing
End Function

Excel-VBA get number from letter equivalent entry in a textbox

I have a user form that asks for a column reference to be entered into a TextBox. I am trying to make it so that the number replaces the letter in the code. I am using the Cells(a,b) format to do this. Which is why I need the number to replace the letter.
Worksheets("AIO").Cells(X, TextBox3).Value = Worksheets("FDSA").Cells(Y, TextBox4).Value
Hence in the previous code when: x=2, TextBox3.Value=A, y=4, and TextBox4.Value=AA
The code will work as
Worksheets("AIO").Cells(2, 1).Value = Worksheets("FDSA").Cells(4, 27).Value
The only thing I can think of making is a huge if statement were I code something similar like this:
If textbox3.value ="A" then
textbox3.value=1
elseif textbox3.value=E then
textbox3.value=5
.......
.......
textbox3.value=AD then
textbox3.value=30
End If
If you want to keep it uncomplicated, .Cells can use the column string instead of number
Sub test()
'From sheet module
Debug.Print Me.Cells(1, 1).Address 'prints $A$1
Debug.Print Me.Cells(1, "A").Address 'also prints $A$1
End Sub
You might have to validate that it's a valid column ID but you probably need to do that even converting it to a number.
On way to get a column number from a character string:
Sub ColumnNumber()
Dim s As String
Dim L As Long
s = "AB"
L = Cells(1, s).Column
MsgBox L
End Sub

How to aggregate returns in an excel UDF using the product formula

I am trying to put the below formula into a UDF so that I can get a cumulative return when I aggregate monthly returns.
In excel the formula has to be recognized as an array so when I type it in I press Ctrl + Shift + Enter to get the {} brackets around the formula.
Does anyone know how to do this?
I want to be able to just type in returns_calc() and select the range that would fit into the returns variable below.
{=(PRODUCT(1+returns/100)-1)*100}
You can use the [ ] notation in Application.Evaluate to calculate Array Formulas in VBA. Your above formula can be called in VBA in just 1 line as shown below
Sub Sample()
MsgBox Application.Evaluate(["=(PRODUCT(1+returns/100)-1)*100"])
End Sub
Now modifying it to accept a range in a function, you may do this as well
Function returns_calc(rng As Range) As Variant
On Error GoTo Whoa
Dim frmulaStr As String
frmulaStr = "=(PRODUCT(1+(" & rng.Address & ")/100)-1)*100"
returns_calc = Application.Evaluate([frmulaStr])
Exit Function
Whoa:
returns_calc = "Please check formula string" 'or simply returns_calc = ""
End Function
EXAMPLE SCREENSHOT
Something like this
Public Function Range_Product(theRange As Variant)
Dim var As Variant
Dim j As Long
var = theRange.Value2
Range_Product = 1#
For j = LBound(var) To UBound(var)
Range_Product = Range_Product * (1 + var(j, 1) / 100)
Next j
Range_Product = (Range_Product - 1) * 100
End Function