Extract 1st letter from cell concatenate with another cell paste in third cell, then next row - excel

Question

I need to extract 1st letter from cell B2 concatenate with cell C2 paste in cell A2,
then move to next row and repeat till last data row.
I have the following, which partially works, but only works for the first row A2 then fills down this one string through all the rows till last data row.
Sub UserName()
Dim rng As range
Dim lastRow As Long
With Sheets("sheet1")
lastRow = .range("E" & .Rows.Count).End(xlUp).Row
End With
For Each rng In Sheets("Sheet1").range("A2:A" & lastRow)
rng.Value = fUserName(rng.Value)
Next
End Sub
The function
Function fUserName(ByVal strUserName As String) As String
Dim r As String
r = range("B2").Select
strUserName = Left(Trim(r), 1) & " " & range("C2")
fUserName = strUserName
End Function

Answer 1

IMHO you don't need VBA for that. Just use formula in A2
=CONCATENATE(LEFT(B2, 1),C2)
And then just replicate it for all cells that contain data.

Answer 2

Try below code. I have combined both your procedure.
No need of using a function , No need of For each loop
Sub UserName()
Dim lastRow As Long
With Sheets("sheet1")
lastRow = .Range("C" & .Rows.Count).End(xlUp).Row
End With
Range("A1:A" & lastRow).FormulaR1C1 = "= left(RC[1],1) & RC[2]"
End Sub

Answer 3

Your function is wrong, you are passing strUserName to the function but then setting the same variable within the function, however the real source of your issue is that you are using static references in your function so it does not matter which cell your sub routine is dealing with the function looks a cells B2 and C2.
I would get rid of the function all together and just replace the line
rng.Value = fUserName(rng.Value)
With
rng.Value = Left(Trim(rng.offset(0,1)), 1) & " " & rng.offset(0,2)
If you really want to use a function you need to pass the range to the function, not the value of the active cell as this has no bearing on the values of the other cells around it.

Answer 4

You need to pass the range into the function:
Sub UserName()
Dim rng As range
Dim lastRow As Long
With Sheets("sheet1")
lastRow = .range("E" & .Rows.Count).End(xlUp).Row
End With
For Each rng In Sheets("Sheet1").range("A2:A" & lastRow)
rng.Value = fUserName(rng)
Next
End Sub
Function fUserName(rn as Range) As String
fUserName = Left(Trim(rn(1,2).value), 1) & " " & rn(1,3).value
End Function

Answer 5

Well obviously B2 and C2 are hardcoded values so they do not change. You need to make those change by using a range object, for instance. Here's a pseudo-code of what I would do. I leave it up to you to make the necessary adjustments to make it work (because I don't see much effort in your question).
Function fUserName(rng as Range) as String
fUserName = Left(Trim(rng.Offset(0, 1).value), 1) & " " & rng.Offset(0, 2).value
End Function
Instead of calling fUserName() with rng.value, just put in rng. This will use the range object to get the proper rows for B and C.

Answer 6

Following code select first blank row
Sub SelFrstBlankRow()
Dim r1 As Range, r2 As Range, r3 As Range
Set r1 = Sheets("Sheet1").Range("a20")
Set r2 = Sheets("Sheet1").Range("u20")
Set r3 = Range(r1.End(xlUp), r2.End(xlUp)) 'r3 is the 1st blank row
r3.Select
End Sub