Using named ranges and worksheet functions in Excel VBA

Bold Brackets

A couple of days ago I saw something in an article on StackOverflow, that blew my mind. I can’t find the article anymore, but I do remember what this one neat trick was, that will for ever change your VBA. It’s called a named range, and I found out I had always been doing it wrong. So have you, most likely.

Have you ever written something like this?


s = Application.WorksheetFunction.Sum(Range("A1:A10"))

You thought you were quite smart, using SUM to add some values together that would have taken a loop in VBA. You petted yourself on the back, took a beer, and applauded yourself for you being awesome. Well, you’re not awesome. This is lame. You suck. Ok, maybe not, but watch this:


s = [Sum(A1:A10)]

It’s incredible! This gives the exact same result.  You may wish to prepend with a sheet name, so it’s an exact reference. You can use any kind of name inside the square brackets. So, if A1:A10 is named ‘records’ in Excel you could rewrite this code to


s = [Sum(records)]

Note that with this notation we don’t use double quotes around the name of the range.

Vanishing Variables

CaptureA quite mighty use for this, is that we can now write code with a lot less variables, if we let Excel do the work for us.

  1. make a new sheet
  2. name it ‘variables’
  3. make three columns: name, value, description

Now you can fill the table you just made with all kinds of settings, constants or calculations that you want to use in your elaborate VBA program.

I am a lazy teacher, and I have a lot of students, so I work a lot with short macros that can help me get more spare time. Here’s an example:

    For Each subfolder In FSfolder.SubFolders
        If subfolder Like "Student *" Then
            [studentNr] = Right(subfolder, 6)
            If Not FileExists([sClass]) Then
                FS.createFolder [sClass]
            End If
            FS.MoveFolder subfolder, [newFolder]
        End If
    Next subfolder

In line 3 I fill the named range ‘studentNr’ with a value taken from a folder, which contains a student number. In the next line, I check if a folder for that students’ class has already been made, and if not, I make the folder. The variable [sClass] does not exist in my code. It only exists in my variable table in Excel. The cell contains a VLookup function to find in which class this student is currently enrolled. Similarly I have a [Teacher] variable, also with a VLookup function. NewFolder is simply a concatenation and formatting, which is also easily done in Excel.

As you can see, the values for [sClass], [Teacher] and [newFolder] are filled automatically by Excel, and I don’t have to process anything.

Programming like this in Excel is a new paradigm. You don’t churn out all your code top-to-bottom as you used to. You create sheets with lots of calculations, lookups etc, and then you make a tiny program that links all this together. Excel can do some crazy fast, complex stuff, and you should never have to program those anymore!

Crazy Caveats

Well wasn’t that incredible? You may not be used to programming like this, and I recommend this method only for experts. You should be in full control of the worksheets, or otherwise someone will mess with your program. Also, when you are part of a team, you should make sure this ‘magic’ is elaborately documented in the code (e.g. in a header of the function mention which Excel named ranges are used).

Good luck.

Learn more: FastExcel Blog

 

The selection contains multiple data values… Merging cells in Excel.

This is a super powerfeature I have always missed in Excel: the ability to join the content of cells without losing any data. Sorry, what’s that?? Yes, I know about the ‘merge’ option. It’s lame! Try merging two cells that both have content. Excel answers, delightfully happy, that you will only keep data in the first cell and lose all of the data of the other cells, and go deal with it.

multiple-data
multiple-data

So, I decided to ‘deal with it’ and I present here several macros for your pleasure and entertainment that will solve this once and for all.

Merging, Joining and Combining

Well, that’s all the same of course. Let’s start with a simple macro to join a bunch of cells and put the result in the first cell.

Sub Join()
   Dim out As String
   Dim c As Range

   out = ""
   For Each c In Selection.Cells
      out = out & c.Value
      c.ClearContents
   Next
   Selection.Cells(1, 1).Value = out
End Sub

How does it work? First, we define the variable out which will contain all content. Then we loop over all cells in the current selection and we combine their values using the concatenation operator “&”. Finally we put the value of out in the first cell of the selection.

If you have never created a macro before, you can add them by pressing ALT+F11. After that, make sure to copy this one to the personal macro workbook.

In some occasions I needed to merge, but also keep the data separated by either commas or newlines. So I made a slightly modified version with arguments. Note for noobs: you can’t run these like normal macros, you’d have to go into the VB editor and start them from the immediate window. Or, you can make a short calling-macro similar to the JoinWithBreaks below.

' join the contents of a selection of cells
' and put all of these together in one single cell
Sub Join(Optional s As String = "", Optional wrap As Boolean = True)
    Dim out As String
    Dim c As Range
    Dim n As Integer

    out = ""
    For Each c In Selection.Cells
        n = n + 1
        out = out & c.Value
        If n < Selection.Cells.Count Then
            out = out & s
        End If
        c.ClearContents
    Next
    Selection.Cells(1, 1).Value = out
    Selection.Cells(1, 1).WrapText = wrap
End Sub

Sub JoinWithBreaks()
    Join vbNewLine, True
End Sub

Fillerup

Another problem closely related to the merge problem is when you have a sheet looking like this:

excel fill problem
excel fill problem

And let’s say it extends a long long way to the bottom for your archive of ten years. To create a usable Excel table and e.g. to create a pivot table your table needs to have values in every cell, not just the first one. Humans can reason that cell A3 also belongs to January, but computers and thus Excel cannot. Clicking on the autofill handle in cell A2 fixes this, but doing so for 100 cells is still very tedious work. For that, we can use the following macro, which will automagically fill every empty cell with the value right above it.

Sub Filler()
    Dim c As Range

    For Each c In Selection.Cells
        If IsEmpty(c) And c.Row <> 1 Then
            c.FormulaR1C1 = c.Offset(-1, 0).FormulaR1C1
        End If
    Next
End Sub

Cybernetic Programming

cybernetics

I’d like to make a proposal for a new kind of programming (at least new to me, LOL). When I was studying back in the nineties I became interested in something called ‘sociocratic organization‘. This is a form of organization based on Cybernetics. Cybernetics is the study of systems with feedback loops. When you think of a thermostat in the room, it has a feedback loop. When it gets too hot, it cools, when it gets too cool, it warms up, and that way it keeps the system in balance. In computer programming we don’t deploy such features normally. We pray that all goes well, and that we didn’t forget anything, and if it does go wrong, the whole system usually crumbles apart. In web programming that’s usually a minor glitch, since just one page of our whole system breaks. In desktop computing it’s much worse. And in embedded programming it’s disastrous. Now instead of writing numerous unit tests, or mathematically proving our program, perhaps it would be possible to use this idea of a feedback loop in many aspects of our programming.

Consider you have to write a program that is to determine the best results for a search, similar to Google (but not as vast, so let’s say a small web site). We need to display what’s relevant to the user, but we don’t know what is relevant. So you just do a simple text search to find a record within a table. Now you check which of the results is clicked for this particular search result, and then you log the search term, and with it the clicked result.

Then a new user shows up and does the same search, and clicks the same result. You increment the counter for this result on this search in the log. After a while we should see our statistics in the table represent what people were searching for, and which records were ‘successful’ to them (at least they clicked it). Depending on these results you can now decide to alter the order of the search results, where the highest scoring record is put on top of the search results page.

Pretty nifty. I Googled it and found that Microsoft Research has written a paper on something similar. So expect this to Bing us soon.

Convert Excel date value to SQL date

When creating SQL statements you’ll often need a date in the ISO 8601 standard format (e.g. 2010-03-26 12:34).

Of course you can change the format in Excel to show it as such, but that doesn’t give you the string you need, e.g. in an insert or update statement.

Here’s an Excel function to make an SQL date value, presuming the date value is in cell A1:

=TEXT(A1,”yyyy-mm-dd hh:MM:ss”)

This circumvents the use of complicated IF and date/time functions. Append a “Z” if you need to indicate the timezone as UTC (i.e. GMT) time.

Here’s a short VBA function to create this type of date

Function SQLDate(d)
SQLDate = WorksheetFunction.Text(d, "yyyy-mm-dd hh:MM:ss")
End Function

Put this code in a new module in your workbook to instantly start using the function in Excel like this: “=SQLDate(A1)”

SQL date in Excel
SQL date in Excel

More information:

http://en.wikipedia.org/wiki/ISO_8601

A dead simple, lightweight javascript calendar

calendar-size-badgeI recently needed a good light weight javascript calendar but couldn’t find it. The problem is that online I could find many calendars, but they all suffered from one of two problems: they were either too heavy, or they were badly written (aka coding like it’s 1999).

I hereby present a very lightweight javascript calendar object. It can be used anywhere where you need to select a date.

It features the following:

  • no library. That’s right, it does NOT use mootools, it does NOT use jQuery.
  • clean code. Yes it can be improved, but that would make it a heavy calendar again.
  • it does not do Date magic. If you want date magic I can recommend date.js. (oh, and that means things like ‘3 days ago’ etc.)
  • it’s lightweight, mainly because it doesn’t do magic and it doesn’t have a library. It’s 2K uncompressed, 1.5K using dean edwards packer.
  • no popup windows. All

Download

Download mbcalendar 1.0

Usage

var cal = new MBCalendar('inp', 'btn', 'click');

Where

  • inp is the id of the input that will be retrieving the calendar, and
  • btn is the id of the element that will trigger the calendar to show, and
  • click is the name of the event that will trigger the calendar
  • in the onload script, in this example ‘out’ is the id of the element that will hold the calendar.

This way it can be used as a date picker, but it can also be used as a visible calendar with navigation (static). Basically the output is simply the HTML, so you can use it anywhere.

All dates van be individually styled, since they all get a unique id. Also all dates get class names so you can style either a certain year, month, or day of the month. E.g. ‘.y2009’ will style every date in 2009, ‘.m3’ will style every march, and ‘.y2009.m3’ will style every day in March, 2009.

Source code

Now for the code

/*(c) Michiel van der Blonk 2009 - license: http://www.opensource.org/licenses/mit-license.php*/

function MBCalendar(m, y)
{
this.m = m;
this.y = y;
this.weekDays = ['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday'];
}

MBCalendar.prototype.$ =  function(s) {return document.getElementById(s)};

// export as array
MBCalendar.prototype.toArray = function() {
var d;
var dates = [];
for (var i=1;i<32;i++)
{
d = new Date(this.y,this.m-1, i);
if (d.getMonth() == this.m-1)
dates.push(d);
}
return dates;
};

// export as html
MBCalendar.prototype.toHTML = function() {
var i;
var ret, dayId, dayClass;
ret = dayId = dayClass = '';
var dates = this.toArray();
ret += '
<table class="cal">' + '
<tr>';
for (i in [0,1,2,3,4,5,6])
ret += '
<th>' + this.weekDays[parseInt(dates[i].getDay())].substr(0,1) + '</th>
';
ret += '</tr>
<tr>';
for (i in dates)
{
var d = dates[i];
if ((parseInt(i) % 7) == 0)
ret += '</tr>
';
if ((parseInt(i)+1 % 7==0) && i<dates .length)
ret += '
<tr>';
dayClass = 'y'+d.getFullYear() + ' m' +(d.getMonth()+1) + ' d' + d.getDate();
dayId = 'day-' + parseInt(d.getTime()/86400000);
ret += '
<td id="' + dayId + '" class="' + dayClass +'">' + dates[i].getDate() + '</td>
';
}
ret = ret + '</dates></table>
';
return ret;
};

window.onload = function() {
var $ = function(s) {return document.getElementById(s)};
var c;
$('showCal').onclick = function() {
var y = $('year').value;
var m = $('month').value;
c = new MBCalendar(m, y);
$('out').innerHTML = c.toHTML();
};
$('prev').onclick = function() {
var d = new Date(c.y,c.m-2,1);
c = new MBCalendar(d.getMonth()+1, d.getFullYear());
$('out').innerHTML = c.toHTML();
}
$('next').onclick = function() {
var d = new Date(c.y,c.m,1);
c = new MBCalendar(d.getMonth()+1, d.getFullYear());
$('out').innerHTML = c.toHTML();
}
};

If you like you can integrate the prev, next and show methods in the Calendar object itself of course. I invite all javascript experts to crunch the code even more, without making it unreadable!

If you don’t integrate that code, you will need to add some standard HTML in a page to get a functional Calendar demonstration:

<input type="text" id="year" value="" />
<input type="text" id="month" value="" />
<button type="button" id="showCal">Show Calendar</button>
<button type="button" id="prev">prev</button>
<button type="button" id="next">next</button>

Some alternative calendars you might like:

update: there was still some debug code in there, it’s removed now. Also it seems wordpress messes up the code when I paste it. Change line 16 to have the ‘<‘ char instead of &lt;

How to shuffle an array

This is a very common programming problem, e.g. when you wish to show some images in random order, when you want to show a random quote, etc. I will show you a solution in JavaScript, but it can be ported to other languages easily.

The common solution to shuffling is to swap random elements, but swapping means you have to constantly work with two elements, and it can be done by using only one. Also, it’s common to randomly swap e.g. 1000 elements, but that wouldn’t work well for very large arrays.

All you have to do is follow a couple of simple steps:

  1. First, of course you start with a simple array, which you have in a specified order.
  2. You place a random element in the output array, and remove the element
  3. Repeat step 2 until the array is empty

Here’s the full code

function shuffle(r) {
	var pos;
	var out = [];
	while (r.length > 0)	{
		pos = parseInt(Math.random()*r.length);
		out.push(r[pos]);
		r = r.slice(0,pos).concat(r.slice(pos+1, r.length));
	}
	return out;
}

Let’s examine the parts. First, the variables pos and out are defined, and out is initialized to an empty array.

	var pos;
	var out = [];

No we “loop” through the array. But, do note that this is not a real loop, in fact we’re constantly going to remove elements until the array is empty. So the simple check on length is enough here.

	while (r.length > 0)	{

We find a random element. For large arrays the Math.random() method can be considered unreliable, but then I mean really large.

		pos = parseInt(Math.random()*r.length);

Next, we add the random element to the output array, using push. Then we remove the element from the original array. This is done in three parts:

  1. get everything on the left of the element
  2. get everything on the right of the element
  3. concat these two arrays to form a new array

That is a really difficult way of removing just one element, but deleting an element from an array is not a native javascript method. John Resig wrote another version of delete

		out.push(r[pos]);
		r = r.slice(0,pos).concat(r.slice(pos+1, r.length));

And last but not least we return the new array:

	}
	return out;
}

Example

Here’s an example of calling the function, shuffling 52 integers

var r=[];
i=52;
while (i--)
	r.push(i);
alert(shuffle(r).join(','));

Extending Array

If you feel so inclined you can make it an extension of the Array object in javascript, like so:

Array.prototype.shuffle = function() {
	var r=this;
	... //rest of code
}

Note the additional "r=this" line.

Drawbacks

There are some drawbacks and warnings to take note of:

  • It can be slow for huge arrays, I would recommend it for arrays under 1000 items
  • It takes up additional space, since it creates a new array
  • The delete can be improved, by using e.g. John Resig’s version

A shorter ‘hack’

The following is a short hack that can most definitely suit one time needs. It’s a form of sorting randomly, which sounds weird, and it is, but it works. However, if the random value is not seeded again, the next time you run it you end up with the exact same sequence.

function shuffle(r) {
  r.sort(function() { return Math.random() } );
}

For more background see e.g. the Fisher Yates shuffle method (which by the way this is not, but this is).

Convert Excel Tables To Lists

note: please see the update on the bottom of this article for an even quicker way to convert a table

In a dark past I was an Excel instructor (among other things). I have trained countless people in the art of Excel number wizardry. I have then become a certified Excel VBA specialist, and I must say, in my years being a professional programmer, this is the skill that has set me apart from all other programmers around me. Sure, people can do Regular Expressions… So can I. Sure, people can do Object Orientation. So can I. But what programmer fancies dumb jumbling of data, and programming a language that has the word ‘basic’ in it? Right. Most programmers I knew were Linux shell companies (pun intended) that had no idea something good was hidden up the sleeve of Microsoft. But ok, sometimes I was able to show them some awesome things, and they would instantly recognize that their world view (Excell is for end-users) was a grave mistake.

What fun it was to teach people Excel, and more so, VBA! To me, it’s the tool of all tools, and it can greatly help anyone who ever works with data (ehm, anyone). So in this first part of a long, long series (I hope) I will show you, the humble ignorant user how to convert an Excel table to a list.

Why? Many times I have gone to companies and helped them with some particular problem. Usually it started out with an analyst/marketer/ceo showing me a bunch of data. The data was always presented as a table, with column headings and row headings, with the data in the middle. That seems like a nice way to present data, yes, it is in fact. The first thing I would do is then convert this table to an ugly list.

So why would you convert it to a list?

Because Excel is in love with lists. Excel craves lists, it’s like Access’ little brother, but it can speak five languages and juggle 4 balls. It’s no database tool (maximum of 65535 rows, 1M in Excel 2007)… but it can transform any list into a deep, deep analysis.

The way this analysis is done later on is with Pivot Tables. I wrote those capitals on purpose. Pivot Tables are so powerful that you can basically give it any data list and it can tell you what’s missing, what’s wrong, what’s unique, what’s the total, what’s the average, you name it. But more on that later on.

Let’s convert!

Warning: code ahead…

A table consists of three parts:

  1. The row headings (left)
  2. The column headings (top)
  3. The data (center)

We will loop through the data cell by cell, and create a row in a new list for each. That’s the basic idea (pun intended).

Before we start, we check some preconditions. We have to make sure that we are inside a set of data, formed into a table. All we do is just check if we have at least two rows and two columns (not the ultimate, but it works).

Sub TableToList()
If ActiveCell.CurrentRegion.Rows.Count < 2 Then
Exit Sub
End If
If ActiveCell.CurrentRegion.Columns.Count < 2 Then
Exit Sub
End If

Then we will need some variables to refer to the various sections of the table

Dim table As Range
Dim rngColHead As Range
Dim rngRowHead As Range
Dim rngData As Range
Dim rngCurrCell As Range

Next. we will need some variables for the data itself

Dim rowVal As Variant
Dim colVal As Variant
Dim val As Variant

Now, we will start pointing our variables to the data, row headings and column headings, like so

Set table = ActiveCell.CurrentRegion
Set rngColHead = table.Rows(1)
Set rngRowHead = table.Columns(1)
Set rngData = table.Offset(1, 1)
Set rngData = rngData.Resize(rngData.Rows.Count - 1, rngData.Columns.Count - 1)

Note that “currentregion” is a handy tool that expands any cell into a surrounding of non-empty cells. So this way your selected cell could be anywhere inside the table when you run the macro. The data part is a bit harder, line 4 and 5 together shift and resize the original table to form the right bottom part, where all the data resides.

ActiveWorkbook.WorkSheets.Add

Next, we create a new sheet in the workbook, to hold the list.

ActiveCell.Value = "Row#"
ActiveCell.Offset(0, 1).Value = "RowValue"
ActiveCell.Offset(0, 2).Value = "ColValue"
ActiveCell.Offset(0, 3).Value = "Data"
ActiveCell.Offset(1, 0).Select

In this sheet, we create a first row, “manually”, where we name the column headings for our list. These column headings are very important for sorting, analysis, pivot tables, export and such. The last statement instantly moves the current cell selection one row down. Notice we’re inserting a special column for Row Number. This is not always necessary, but it doesn’t hurt, and it helps you to always be able to restore the original order of the list.

Now it’s time for the actual grunt work, looping through the table

Dim n As Long
For Each rngCurrCell In rngData
colVal = rngColHead.Cells(rngCurrCell.Column - table.Column + 1)
rowVal = rngRowHead.Cells(rngCurrCell.Row - table.Row + 1)

The “for each rngCurrCell in” is a real beauty in VBA. It just runs through any selection, without worries of overflows, row and column numbers, or calculations. In the loop, we set the value of the current column and row. Note that the rngCurrCell.column and rngCurrCell.row are not relative, it’s the actual number of the column/row. So if the tables starts at C3, the first cel is having column=3 and row=3.

n = n + 1
ActiveCell.Value = n

Here, we upped counter ‘n’ and put it in the list.

ActiveCell.Offset(0, 1).Value = rowVal
ActiveCell.Offset(0, 2).Value = colVal
ActiveCell.Offset(0, 3).Value = rngCurrCell.Value
ActiveCell.Offset(1, 0).Select

We do the same trick again to put a new row in the data list on our new sheet. As you can see this part of code is repeated from the part where we created the header. A small improvement would be to create a function named ‘newRow(n, rv, cv, dv)’ to insert a new row with these values.

If, instead of actual values, you prefer to link to the original cell, you can use

ActiveCell.Offset(0, 3).Value = "=" & rngCurrCell.Worksheet.Name & "!" & rngCurrCell.Address

Finish the loop with:

Next
End Sub

Well, that’s it!

Running your code

Make sure to have a table setup in Excel, and click inside the table, it will be automatically selected.

  • Press ALT+F8
  • Select TableToList
  • Click Run

In Office 2003 you can add a shape to your worksheet, right click, and choose assign macro.

  1. Choose Tools > Customize
  2. Choose Macros > Custom menu item -> drag to toolbar
  3. Right click item
  4. Choose Assign macro…
  5. Choose TableToList

Since Office 2007 this option is not available anymore, but you can still right click the ribbon and choose ‘customize quick access toolbar’. From there you can pick the Macro’s category and add the macro.

A new sheet will be created. Take a look at the list. You can try sorting, filtering, analyzing, totalling, and… pivot tables. A pivot table is a dynamically updating table which automatically totals values from a list, and presents them in… a table. Here’s how to re-create the original table from the list:”

  1. Choose Data > Pivot Table
  2. Choose Finish
  3. Drag ColumnValues to the ‘column fields’
  4. Drag RowValues to the ‘row fields’
  5. Drag Data into ‘Drop data items here’

Voila, the list is back. That is, if it was a list of numbers. Pivot Tables are for numeric operations, if you had text in there, it won’t show anything (anything good).

Download

Download the file here:

Table2List.xla

How to install:

  1. Office 2003: to install an XLA you need to go to Tools > AddIns and select the file with the browse button. Make sure the checkbox is enabled.
  2. Office 2007: Click on the Office Button in the left top, then Excel Options, then Add-Ins. Now select Manage… Excel Addins and click Go. Again browse and enable the addin.

You may wish to copy the file to the suggested Add-Ins folder. If you are on a network and wish to share the add-in with others, make sure to keep it on a network drive.

Once the Add-in is enabled you will see a new button that runs the macro. In Office 2007 the button is under the Add-Ins ribbon tab. You can also press ALT+F8, then type ‘Table2List.xla!TableToList’. The macro will be hidden in the XLA file, so you cannot select it.

An even quicker solution

Abu Yahya (see comments) gave me an even quicker solution. All kudos go to him for this.

First, start the pivot table wizard. Now in Excel 2007 and up you may have a hard time finding it! So, right click the quick access toolbar (it’s the bar with tiny icons on the top). Then choose Customize… and select Choose commands from: Commands not in the ribbon. Now find “pivottable and pivotchart wizard” in the list, and add it to the list on the right. You will see a tiny pivottable icon in the toolbar now.

Go on and click that icon, and then:

Step 1. Choose multiple consolidation ranges
Step 2. Choose I will create the page fields
Step 2b. Select Range of the table then Add to
Step 3. Choose New Worksheet
Step 4. Click Finish
Step 5. on the new sheet – Pivot table field list –> uncheck [ ] Row and [ ] Column
Step 6. There will be one value exactly in your pivottable. Double click it.

You will now see a new sheet with a list built up of the columns Row, Column and Value.

Step 7 (optional). Create a pivottable from this list to analyze your data.

One important note: you can have exactly 1 field that will show up in your data next to your row and column fields. That field has to be in the far left column of the data you select before consolidating. If you need more data in your final analysis you can combine fields with the “&” operator, using a formula like e.g.in cell C2:  =A2 & B2.