Showing posts with label Functions. Show all posts
Showing posts with label Functions. Show all posts

Friday, 7 January 2011

MS Access - Replacing Part of a String

Had another issue where we needed to replace a section of a string with another input string, here is the function I came up with.

to use it you need to enter three elements, 1) the String to be changed, 2) The Part to be Removed, 3) The String to Replace it.

so for example ReplaceString("This is the Start","Start","End") Where the String is "This is the Start" and the function will replace "Start" with "End" so that the Output of the Above function is "This is the End"

Function ReplaceString(ByVal strString As String, ByVal strOld As _
String, ByVal strNew As String) As String


Dim lngCount As Long
Dim strChange As String

strChange = strString
lngCount = InStr(strChange, strOld)

Do While lngCount > 0
strChange = Left(strChange, lngCount - 1) & Replacevalue & _
Mid(strChange, lngCount + Len(strOld))
lngCount = InStr(lngCount + Len(strNew), strChange, strOld, 1)
Loop

ReplaceString = strChange

End Function

Wednesday, 28 July 2010

Glookup Function - Combining Vlookup and Hlookup

I have been working on a new Excel function of late as I have always liked Vlookup and Hlookup but as discussed in an earlier post the more you try and do excel the less use they become, the issues I was finding more and more is that I used Match and Offset far more often. The main problem I had is that Vlookup will find a value in the left hand column and return a value, and Hlookup finds a value at the top but what if you have a grid and need to select a value based on a V and an H lookup?

In this case you use Match to find the first value and then use Count and Offset to create the dynamic range for the second, this was fine for one calculation but after writing 100 formulas on each sheet it becomes a pain. Therefore I worked on my new function.

Glookup (Grid Lookup) it works on the same lines as V and H lookup only the two lookup values are also the column return counts.

Here is the Formula broken down =Glookup([Vlookup],[Hlookup],[GArray])

Where Vlookup is the value in the Left Hand Column

Hlookup is Value in Top Row

GArray is the Grid Array (Where your data is – Must include your two header rows)

In the above example therefore =glookup("Feb",2007,A2:K14) would have the result of 23

So how does it work? Firstly I have to say in the interest of fairness and because it would simply be wrong not to, I have to say a big vote of thanks to RomperStomper over at Excelhelp.net who helped me with tidying up the code into a very nice succinct module.

Anyway to use Glookup simply paste the following code into the VBA window of your spreadsheet (Pressing Alt + F11 or going to Tools-Macro-Visual Basic Editor)

Function GLookup(VLookup, HLookup, GArray As Range)

Dim VRef

Dim HRef

VRef = WorksheetFunction.Match(VLookup, GArray.Columns(1), 0)

If IsError(VRef) Then

GLookup = CVErr(xlErrValue)

Else

HRef = WorksheetFunction.Match(HLookup, GArray.Rows(1), 0)

If IsError(HRef) Then

GLookup = CVErr(xlErrValue)

Else

GLookup = WorksheetFunction.Index(GArray, VRef, HRef)

End If

End If

End Function

It should now look like this

Now you can call the function from any worksheet in this book, don’t forget though you will unfortunately have to copy the function into each sheet you want to use it on.

Tuesday, 27 July 2010

Returning Quaterly Values In Excel

I was speaking to a friend earlier who showed me a new way to automatically display quarterly totals using Sum Product.

This Table is set up in A2:D14
In the Quarters Summery sheet enter this formula

=SUMPRODUCT((ROUNDUP(MONTH(A3:A14)/3,0)=2)*(C3:C14))


Now this function has the same effect as simply inputting =SUM(C3:C5) but has the advantage that you can have the same formula in each cell, you select which Quarter you want to return by adjusting the =2 to show which quarter you require (i.e Jan - March is 1, Apr - Jun is 2 etc...)

I think perhaps that the best use for this however is to discourage the occasional excel user from trying to "Improve" your worksheets.

Sunday, 6 June 2010

Nerd Humour and Cross Tab Issue

First a little Nerd joke.

"There are only 10 types of people in the world, those who understand binary, and those who don't."

Anyway,

Have had a slight issue this morning trying to load a crosstab query into a recordset to append to an excel sheet - When does this not bother me at 6am on a Sunday!!

Anyway the issue is in trying to transfer the information to a spreadsheet with the column heads, obviously it is quite easy to transfer the data but the column heads are trickier as with a cross tab query they could be different each time. anyway I managed to sort out a code snip which will populate the column headings.

Private Sub TransferCrossTab()

Dim myQdef As QueryDef
Dim rsReport As Recordset
Dim appXl As Excel.Application
Dim appxlWB As Excel.Workbook
Dim appXlWS As Excel.Worksheet
Dim lngColNbr As Long
Dim xlc As Object

Set myQdef = CurrentDb.QueryDefs("qry_monthlyquery_agb") 'open crosstab query
Set appXl = CreateObject("Excel.Application")
Set appxlWB = appXl.Workbooks.Open(strfilepath, , False)
'open spreadsheet "Here Stored as global variable"
Set appXlWS = appxlWB.Sheets("Source_Data")
Set xlStart = appXlWS.Range("B1")

appXlWS.Range("B1:AY453").ClearContents 'Clear Contents from Spreadsheet
For lngcolNbr = 0 To rsReport.Fields.Count - 1
xlStart.Offset(0, lngcolnbr).Value = rsReport.Fields(lngcolnbr).Name 'For Each Field in Recordset provide column heading
Next lngcolnbr
Set xlc = xlc.Offset(1, 0)
appXlWS.Range("B2").CopyFromRecordset rsReport 'Add Recordset Data

End Sub

Hope this makes sense, Haven't really got time to go over it at present but if this sounds like it may help you feel free to get in touch.

Saturday, 5 June 2010

Null values in Select function - VBA Access

I have been asked about how you can trigger an event in a SELECT CASE when there is a null value. (As you can not have null as a case)

The answer is actually incredibly easy, you use the nz() function, NZ returns a variable you can set when there is a null value, it needs to arguments.

1. the field to be evaluated
2. What to replace the Null value with

nz([Field to be Evaluated],[Value to Return if Null])

in this quick example I want to return a message box if the field is null.

SELECT CASE nz(me.nullfield,0) 'This will replace a null value with a 0
CASE 0
msgbox "Error, value Needed"
CASE "Value 1"
msgbox "Value 1 Selected"
CASE "Value 2"
msgbox "Value 2 Selected"
END SELECT

obviously if "0" is one of your CASE values you can replace it with a string i.e. "None"

Friday, 28 May 2010

Week Ending Function VBA

Just Finished working on a problem for a DB, the client wants all their reporting to be based on Week Ending dates but their files are stored by Date. How can you summarise per week?

I sorted it by creating a function I could then include in my queries -

Public Function WeekEnding(Actual as variant) As Variant
If IsDate(Actual) Then 'Check that variable is a date
WeekEnding = DateAdd("d", Actual, 7-Weekday(Actual)) 'Add on 7 days minus variable day
End If

End Function

Tuesday, 25 May 2010

Access Date Format Issues

I have been asked by a few people how to solve the issue that when you are sending data from Excel to Access (and vice versa) in VBA the dates get flipped into US format :- MM/DD/YYYY instead of DD/MM/YYYY now this will only happen when you the day of the date is less than 12, the issue comes from the way the Excel or Access interperate the date it recieves. annoyingly it does not give any regard to the regional settings.

Anyway the way I found to get around it is using a function to convert the date into a format that can not confuse the system.

Public Function Fixdate(ByVal str)

Dim dteDay
Dim dteMonth
Dim dteYear

If isnull(str) Then
msgbox "Error"
Exit Function
End If

dteDay = Day(str)
dteMonth = MonthName(Month(str), True)
dteYear = Year(str)

FixDate = dteDay & "-" & dteMonth & "-" & dteYear

End Function

This is then used as follows

myDate = fixdate(date)

This will return a value to mydate as 25-May-2010 which Excel or Access will be able to interperate as the correct date.

Monday, 24 May 2010

Trim Address Functions

I have been working on a new database and have found the need to separate a combined text field into various columns, obviously you can do this using the Left and Right Trim functions but how do you trim a combined text field into parts that are not fixed width?

For this example I will use an address field txt_Address which contains addresses of in determinant length. To do this you need to split it up by each address field in this field these are identified by commas

First step therefore is to identify the commas as each comma needs to be placed on a different line.

(Len([txt_Address])-Len(Replace([txt_Address],",","")))/1 This will tell you how many comma’s there are.




As you can see some of the addresses do not have a comma, so when we write our first expression we need to qualify if there is a comma to split by and if not to just add the whole field

Address Line 1 =

IIf(((Len([txt_Address])-Len(Replace([txt_Address],",","")))/1)=0,[txt_Address], Left([txt_Address],InStr(1,[txt_Address],",")-1))



The Address Line 2 query is obviously different for each field depending on how many commas are present, start the expression again by checking how many commas present and if it is less than 1 return a blank field.

IIf(((Len([txt_Address])-Len(Replace([txt_Address],",","")))/1)=0,"",>
If there is a comma however then you need to trim from the first comma
Right(Trim([txt_Address]),Len(Trim([txt_Address]))-InStr(1,[txt_Address],",")


However if there is more than one comma you need to left trim the newly created field to just take the first line. You can do this by replacing the above right trim into the first left trim in place of the field names.
You get a very confusing looking Address Line 2 =
IIf(((Len([txt_Address])-Len(Replace([txt_Address],",","")))/1)=0,"",IIf(((Len([txt_Address])-Len(Replace([txt_Address],",","")))/1)=1,Right(Trim([txt_Address]),Len(Trim([txt_Address]))-InStr(1,[txt_Address],",")),Left(Right(Trim([txt_Address]),Len(Trim([txt_Address]))-InStr(1,[txt_Address],",")),InStr(1,Right(Trim([txt_Address]),Len(Trim([txt_Address]))-InStr(1,[txt_Address],",")),",")-1))) It looks very confusing but it works


If you wish to have more than three address lines then you simply need to keep shortening the trimmed value by one comma at a time until you can “left” the part that you want. For this one however I will place everything else onto a third line for simplicities sake.

This simply uses the above functions in place of the actual field name
Adress Line 3 =
IIf(((Len([txt_Address])-Len(Replace([txt_Address],",","")))/1)=1,"",right(trim(right(trim([txt_Address]),Len(Trim([txt_Address]))-InStr(1,[txt_Address],","))),Len(Trim(Right(Trim([txt_Address]),Len(Trim([txt_Address]))-InStr(1,[txt_Address],","))))-InStr(1,Right(Trim([txt_Address]),Len(Trim([txt_Address]))-InStr(1,[txt_Address],",")),",")))
So the final Query is as follows:
SELECT txt_Address, txt_PostCode, IIf(((Len([txt_Address])-Len(Replace([txt_Address],",","")))/1)=0,[txt_Address],Left([txt_Address],InStr(1,[txt_Address],",")-1)) AS [Address Line 1], IIf(((Len([txt_Address])-Len(Replace([txt_Address],",","")))/1)=0,"",IIf(((Len([txt_Address])-Len(Replace([txt_Address],",","")))/1)=1,Right(Trim([txt_Address]),Len(Trim([txt_Address]))-InStr(1,[txt_Address],",")),Left(Right(Trim([txt_Address]),Len(Trim([txt_Address]))-InStr(1,[txt_Address],",")),InStr(1,Right(Trim([txt_Address]),Len(Trim([txt_Address]))-InStr(1,[txt_Address],",")),",")-1))) AS [Address Line 2], IIf(((Len([txt_Address])-Len(Replace([txt_Address],",","")))/1)=1,"",right(trim(right(trim([txt_Address]),Len(Trim([txt_Address]))-InStr(1,[txt_Address],","))),Len(Trim(Right(Trim([txt_Address]),Len(Trim([txt_Address]))-InStr(1,[txt_Address],","))))-InStr(1,Right(Trim([txt_Address]),Len(Trim([txt_Address]))-InStr(1,[txt_Address],",")),","))) AS [Adress Line 3], (Len([txt_Address])-Len(Replace([txt_Address],",","")))/1 AS [Comma Count] FROM tbl_MainData_agb;
Maybe next time I will just insist that they place each line in a separate field.

Tuesday, 11 May 2010

The Joys of INDIRECT Excel Function



I have just been working on a spreadsheet and have finally solved an issue that has bugged me for a while. I know this has been quite obvious but I have been very slow where this is concerned.



If you want to select a total from each sheet in a workbook you can easily select it using the INDIRECT function.



If you have a spreadsheet containing data on each page, called January, February etc... and you want to make a summery sheet you can use this formula.



=SUM(INDIRECT(L4&"!$H$3:$J$47")) where column L contains your month name and each sheet contains the data you want summed in the grid H3:J47 then when you copy down the month names it will automatically address the range to the correct sheet.



I can't believe I have only just realised this would work.