**What happens when you create a workbook with Dynamic Array Excel (Excel DA) and send it to someone who does not have Excel DA?**

**My free CheckDA tool allows you to check that the workbook you create using Excel DA will not cause problems when opened in prior Excel versions.**

The introduction of Dynamic Array formulas in Office 365 Excel (as of July 2019 rolling out to the Office 365 Monthly Channel) has made a fundamental change to Excel formula behavior and syntax:

- In previous versions such as Excel 2013, Excel automatically used implicit intersection to select a single value from a range in many circumstances.
- In Office 365 Dynamic Array Excel 2016 (Excel DA), Excel treats all formulas as array formulas unless the implicit intersection operator @ is used, and single-cell dynamic array formulas will spill their arrays to surrounding cells.

For workbooks authored in previous versions of Excel compatibility is good: implicit intersections will be silently converted to the new @ syntax.

When workbooks authored in **Dynamic Array Excel (Excel DA)** are opened in previous Excel versions, in most cases the formulas will be silently converted to the old syntax (@ will be removed where possible, and spilling dynamic arrays converted to array (CSE) formulas).

**But it is possible to create formulas in Excel DA which cause difficulties when opened in previous versions.**

**CheckDA** is a free open-source VBA addin that can scan Excel DA formulas, highlight potential backward compatibility problems and optionally convert some problem formulas to more compatible versions.

Excel will only remove @ from a formula where previous Excel versions would have used Implicit Intersection to return a single value from a Range or Named Range or function parameter.

You will be warned by Excel if you try to enter a formula with @ in an unexpected place, but it is still possible to create such a formula. An unexpected @ will create a _xlfn.SINGLE() in previous versions and will result in #Name when calculated.

For example =@A1 will be converted to =_xlfn.SINGLE(A1) because Excel cannot do Implicit Intersection on a single cell.

**CheckDA** will flag such formulas as type** @**

A formula reference to a dynamic array can use the spill reference suffix #. For example =SUM($B$3#) will SUM the entire dynamic array that starts in $B$3. Spill references get converted to _xlfn_ANCHORARRAY(Reference) in previous versions and will result in #Name when calculated.

**CheckDA** will flag such formulas as type **{#}**

Any formula that Excel DA thinks could return an array (even if it is actually only returning a single value) is converted to a CSE array formula in previous versions.

This may or may not produce a backward compatibility problem – you have to inspect these formulas carefully.

**CheckDA** flags these formulas as types:

**{1}**a single-cell non-spilling formula**#**An Excel DA Dynamic Array formula that is spilling or blocked (#Spill!) will be converted to a fixed CSE formula in previous Non-DA Excel versions such as Excel 2013.**{n}**a formula entered in Excel DA as a multi-cell CSE formula

CheckDA is an open-source VBA XLAM addin.

**CheckDA only runs in Windows Office 365 Dynamic Array Excel.**

*To protect against accidental change CheckDA is protected with the password dm.*

**You can download the CheckDA addin from here.** The zip file contains the CheckDA.xlam and the CheckDa.docx Word document.

Install the CheckDA.XLAM file using Excel’s Addin Manager if you want it permanently installed, or just open the xlam workbook using Excel File Open if you only want to use it in the current Excel session. Once successfully installed you will see CheckDA available on the ribbon.

**Control-Shift-J** or clicking the Check DA Formulas button shows the Check DA form.

The form:

- Shows formulas in Non-DA Syntax
- Is Modeless (you can edit formulas while still showing the form)
- Is Resizeable
- At start-up scans
**the active worksheet**for unique formulas - At start-up filters out formulas with unexpected @ or Spill Ref or Spill or single-cell array formulas

Clicking the **Restate Selected Formulas **button will change any @ or {1} formulas selected in the form to more compatible syntax:

- @ formulas will have their unexpected @s removed.
- {1} formulas will be re-entered as non-array formulas.
- # Spill formulas and {#} Spill Ref formulas cannot be automatically restated.

Clicking the **Undo Restate** button will undo the restatement of any formulas restated in this session of CheckDA.

This button toggles between showing the formulas in Non-DA syntax and Office 365 Dynamic Array syntax.

**Please let me know of any bugs you find, and send me your improvement ideas and experiences withCheckDA.**

There is a great list of speakers and a chance to discuss Excel with a Microsoft Dev Team member and a host of Microsoft Excel MVP’s – acknowledged as Experts and Community contributors by Microsoft.

]]>The improvements are too numerous to cover in detail but come under these headings:

- Full support for Dynamic Ranges, Linked Data Types and Rich Data Type Field expressions.
- Integration with Name Manager Pro to explore and debug Named Formulas.
- Explore Data Validation formulas, Conditional Format Formulas as well as cell formulas.
- Support for formulas in 91 languages (thanks to Mourad Louha).
- Resolved many Mac Excel issues.
- Lots of bug fixes!

The previous user interface tried to present too much information

So I simplified, de-cluttered and made it more intuitive.

See my previous post on Explorer Pro for a comparison

Profiling the code showed several areas that could be significantly improved. Some expensive operations such as coloring large precedent ranges are now optional.

This build expires on the 31st of March 2019

]]>Develop Excel gives you a unique opportunity to meet and learn from the leading international developers of the major Excel extension technologies.

You will:

- Gain understanding of the comparative merits of available tools, languages and APIs for building Excel extensions
- Discover the implications for developers and solution builders of Microsoft extensions to core Excel (Co-Authoring, Linked rich data types, built-in Power Query, M Language, Javascript interpreter and APIs, cross-platform common code-base etc.)
- Meet the Developers responsible for:
- Microsoft Excel Extensibility including Javascript
- Excel DNA: .Net and Excel
- PyXLL: Python and Excel
- Planatech XLL Plus: C++ and Excel

- Network with, socialize and meet other Excel developers of Addins and Solutions.

The conference focuses on the two dimensions of Excel Development: the extensions Microsoft are making to the Excel platform and APIs, and the Addins and Solutions that developers can build on this extended base.

This event is a community driven one. There is no profit motive, just a desire to gather the best brains in the Excel extension space together to share knowledge.

*Free sponsorship offer – see Sponsors page for details.*

**Special thanks to Microsoft for hosting us at the new London Reactor, and for sending a speaker from the Development team responsible for Excel extensibility.**

]]>

Formula Explorer Pro supports Windows Excel 2007 through Excel 2016 and Office 365, and also Mac Excel 2016.

And now it’s time for a serious test of Beta version 2.5.

(Beta 2.6 Build 362.792 just uploaded)

For a quick overview of Formula Explorer Pro see https://vimeo.com/272986447

And to download the latest Beta version see http://www.decisionmodels.com/fxl_mgrpro_beta2.htm

Please let me have your feedback, bug reports, suggestions etc.

The Explorer Pro Userform is probably the most complex VBA userform I have ever built.

Because it has to work on both Mac and Windows Excel I cannot use any Windows API calls.

The userform:

- Is modeless
- Resizeable
- Has 3 splitter bars
- Has 2 synchronised Treeview controls and 2 textboxes
- Adaptive positioning of controls, dependent on both mode and expression selection.

I wish I could say I developed all the technology that underlies this, but it relies heavily on Jan Karel Pieterse and Peter Thornton’s VBA Treeview, and Andy Pope’s work on resizeable userforms and splitter bars …

Other major components of Formula Manager Pro are the formula parser, expression builder, formula indenter, expression evaluator and forward/backward formula debugger.

The formula parser splits a formula into token strings in the local language being used, and then translates the token strings into US English (thanks to Mourad Louha for his help with testing and extending this to 91 different languages).

The expression builder assembles the token strings into expressions that can be evaluated (this includes the strange criteria expressions that occur in functions like SUMIFS).

The formula indenter takes the expressions and builds indented formula strings using the indenting rules that the user has chosen.

The expression evaluator evaluates each of the expressions to produce a scalar or array result. Special handling is needed for things like the criteria expressions in SUMIFS and finding the source precedents that functions like MAX, LOOKUP, SUMIFS, SUMPRODUCT etc are pulling from. Designing the evaluator is hard because there are many different ways you can build sub-expressions from a formula like =A1+B2+C3+D4*E5+F6.

Another tricky evaluation problem is correctly handling implicit intersection, particularly for formulas like =VLOOKUP(A:A,B:F,G:G,H:H) because some of the arguments do implicit intersection and others (B:F) do not. This requires a lookup table for every argument of every native Excel function.

The step-by-step formula debugger actually drove some of the design choices in the expression builder because it requires an unambiguous set of expressions to can be condensed to results for replacing the expression string in the indented formula.

**Anyway this is why we need an extended Beta test period!**

The Excel team has made a number of performance improvements to Excel 2016. These improvements were rolled out as part of the Office update cycle. The timescale that updates become available to you depends on which update option you are using:

- Insider
- Monthly Channel
- Semi-annual Channel

For more details on the Office 2016 release cadence names see Slow – Fast Level Names.

This post discusses some of the features that have been introduced in Excel 2016 that you can use to improve performance with large or complex workbooks.

Although 64-bit Excel has extremely large virtual memory limits, 32-bit Excel has been limited to 2 Gigabytes (GB). And many Excel customers have found it difficult to migrate to 64-bit Excel because they use third-party addins and controls that are not available in 64-bit versions.

LAA has now been enabled for 32-bit versions of Excel 2013 and Excel 2016, and will minimize out of memory error messages.

LAA doubles available virtual memory from 2GB to 4GB when using 64-bit Windows, and increases available virtual memory from 2GB to 3GB under 32-bit Windows.

For more details see LAA Capability Change for Excel

To download a tool that shows how much virtual memory is available and how much is being used see Excel Memory Checking Tool

Previously, workbooks using large numbers of full column references and multiple worksheets, for example `=COUNTIF(Sheet2!A:A,Sheet3!A1)`

, might use large amounts of CPU and memory when opened, or rows were deleted.

An improvement in Excel 2016 build 16.0.8212.1000 substantially reduces the memory and CPU used in these circumstances.

*My test on a workbook with 6 million formulas using full column references failed with an Out of Memory message at 4 GB of virtual memory with Excel 2013 LAA and with Excel 2010 but only used 2 GB virtual memory with Excel 2016*.

In some circumstances editing Excel Tables where formulas in the workbook use Structured References to the Table could be slow with Excel 2013 and previous versions. This led to the perception that Tables should not be used with large numbers of rows.

Excel 2016 has now fixed this problem.

*My test showed an editing operation that took 1.9 seconds in Excel 2013 and Excel 2010 took about 2 milliseconds in Excel 2016.*

For more details see Why Structured References are Slow in Excel 2013 but fast in Excel 2016.

The Excel 2016 team studied a number of large workbooks that show slow response when using Filtering, Sorting and Copy/Pasting, and a number of improvements have been made:

In Excel 2013 after Filtering or Sorting or Copy/Pasting many rows Excel could be slow responding or would hang. Performance was highly dependent on the count of all rows between the top visible row and the bottom visible row. An improvement made to the internal calculation of vertical user interface positions in build 16.0.8431.2058 has made these operations much faster.

Opening a workbook with many filtered or hidden rows, merged cells or outlines could cause high CPU load.

A fix in this area was introduced in build 16.0.8229.1000

In the past you could see very slow response after pasting a copied column of cells from a Table with filtered rows where the filter resulted in a large number of separate blocks of rows.

This area has been substantially improved in build 16.0.8327.1000

*My test on copy pasting 22000 rows filtered from 44000 rows showed a dramatic improvement:*

- For a Table the time went from 39 seconds in Excel 2013 and 18 seconds in Excel 2010 to 2 seconds in Excel 2016
- For a Range the time went from 30 seconds in Excel 2013 and 13 seconds in Excel 2010 to virtually instantaneous in Excel 2016

In Excel 2013 copy/pasting cells containing conditional formats could be slow.

This has been significantly improved in Excel 2016 build 16.0.8229.0

*My test on copying 44000 cells with a total of 386000 conditional format rules showed a substantial improvement:*

- Excel 2010: 70 seconds
- Excel 2013: 68 seconds
- Excel 2016: 7 seconds

My test on Excel 2016 build 16.0.8431.2058 shows a 15-20% speed improvement compared to Excel 2013 when adding and deleting large numbers of worksheets. However Excel 2016 was 5-10% slower than Excel 2010 on this test.

Excel 2016 build 16.0.7920.1000 introduced several very useful new worksheet functions:

**MAXIFS** and **MINIFS** extend the **COUNTIFS/SUMIFS** family of functions. These functions have good performance characteristics and should be used to replace equivalent array formulas.

**TEXTJOIN** and **CONCAT** let you easily combine text strings from ranges of cells. These functions can replace the slow VBA UDFs typically used in previous versions.

You can find more details of all the other month-by-month improvements that have been made to Excel 2016 at

What’s new in Excel 2016 for Windows.

]]>

The first thing to do is to decide what you mean by “The Last Row” – some possibilities are:

- The row Excel considers to be the last row (last row in the Used Range)
- The last row on a sheet that actually contains data
- The last row in a range that actually contains data
- The last data row in a Table ignoring the Totals row
- The last visible row containing data
- …

The test data is constructed to test different last row VBA strategies for ranges and tables.

- There is a Table in cells $A$4:$A$25. The Table (called Table1) has a header row and a total row.
- There is a Named Range (called NamedRange) in cells $E$4:$E$30 but $E$26:$E$30 are empty.
- Rows 5:8, 13:15, 21:25 and 40:42 are hidden so that the Table and Name Range contain more than one visible region.
- There is data in row 32 below the Table and the Named Range.
- There is formatting in the hidden row 42.

I will look at some of the available strategies for finding the last row.

Because Excel internally uses a sparse matrix scheme for the cells in each worksheet (instead of holding a gigantic 16384 by 1048576 array) it has to store information for each cell that has been used. So formatted cells are considered used, as well as cells containing values and formulas. Cells remain flagged as used even when all formatting, values and formulas are removed.

Two VBA methods for working with the used range are Worksheet.UsedRange and the xlCellTypeLastCell option of SpecialCells.

' ' last row in used range ' jLastUsed = oSht.UsedRange.Rows(oSht.UsedRange.Rows.Count).Row ' ' last visible row in used range ' jLastVisibleUsed = oSht.Cells.SpecialCells(xlCellTypeLastCell).Row

For my test data jLastUsed returns 42 because there is some formatting on that row, and xlCellTypeLastCell returns 39, which is the last visible row before row 42.

These VBA methods mimic pressing Ctrl and the up and down arrows.

For name ranges they skip hidden rows but stop at the row before an empty cell.:

' ' last visible cell in Named Range using End(xlUp) ' jLastVisibleRange = oSht.Range("NamedRange").Offset(oSht.Range("NamedRange").Rows.Count, 0).End(xlUp).Row ' ' last visible cell in Named Range using End(xlDown) ' jLastVisibleRange2 = oSht.Range("NamedRange").End(xlDown).Row

When using End(xlUp) you want start outside the range in an empty cell, so I used Offset to get to the first row below the range. jLastVisibleRange returns 20.

Using End(xlDown) is simpler for a Range: the code start at the first row in the range and ends at the first of the last visible row in the range that contains data and the last row before an empty cell. It also returns 20.

But for Tables End(xlUp) does NOT skip hidden rows!

' ' last row in Table using End(xlUP) - Note End(xlUp ) behaves differently for tables - includes hidden rows ' jLastInTable2 = oSht.Range("Table1").Offset(oSht.Range("Table1").Rows.Count + 1, 0).End(xlUp).Row ' ' last visible table row using End(xlDown) ' jLastVisibleTable = oSht.Range("Table1").End(xlDown).Row

So using End(xlUp) starting from the first row after the end of the table returns Row 25 even though that row is hidden.

But End(xlDown) works the same way with a table as with a Range, and so returns row row 20 which is indeed the last visible row in the table.

My favourite method is to use Range.Find.

Using Find on Formulas includes hidden rows, whereas using Find on Values excludes hidden rows.

You can use this method on Worksheet.Cells or on a Range or Table.

' ' last row containing data (using Find in formulas) ' jLastRangeData = oSht.Range("NamedRange").Find(What:="*", LookIn:=xlFormulas, SearchOrder:=xlByRows, SearchDirection:=xlPrevious).Row ' ' last visible row containing data (using Find in values) ' jLastVisibleRangeData = oSht.Range("NamedRange").Find(What:="*", LookIn:=xlValues, SearchOrder:=xlByRows, SearchDirection:=xlPrevious).Row ' ' last row containing data (using Find in formulas) ' jLastTableData = oSht.ListObjects("Table1").Range.Find(What:="*", LookIn:=xlFormulas, SearchOrder:=xlByRows, SearchDirection:=xlPrevious).Row ' ' last visible row containing data (using Find in values) ' jLastVisibleTableData = oSht.ListObjects("Table1").Range.Find(What:="*", LookIn:=xlValues, SearchOrder:=xlByRows, SearchDirection:=xlPrevious).Row

- jLastRangeData returns 25
- jLastVisibleRangeData returns 20
- jLastTableData returns 25
- jLastVisibleTableData returns 20

Sometimes its simpler to just count the number of rows, add the starting row number and subtract 1.

‘

‘ last cell in Named Range

‘

jLastInRange = oSht.Range("NamedRange").Offset(oSht.Range("NamedRange").Rows.Count – 1, 0).Row

‘

‘ last row in named range current region

‘

jLastInRegion = oSht.Range("NamedRange").CurrentRegion.Rows.Count + oSht.Range("NamedRange").Row – 1

‘

‘ last row in Table

‘

jLastInTable = oSht.ListObjects("Table1").Range.Rows.Count + oSht.ListObjects("Table1").Range.Row – 1

‘

‘ last data row in table (excludes total row)

‘

jLastTableDataRow = oSht.ListObjects("Table1").ListRows.Count + oSht.ListObjects("Table1").Range.Row – 1

- jLastInRange returns 30 (it counts the empty cells too)
- jLastInRegion returns 25 (it excludes the bounding empty cells)
- jLastInTable returns 25
- jLastTableDataRow returns 24 (ListObject.ListRows excludes the total row and header row so I have not subtracted 1 for the header row)

I was really surprised to find that End(xlUP) worked differently for Tables than for Ranges.

And with Tables sometimes it seems best to work with a Range that represents the table rather than directly with ListRows: the syntax is not always obvious to me.

There are many different ways of finding End rows but mostly I use range.find as the most fool-proof method (but there are still snags with things like Merged cells).

**What’s your most frequently used method?**

**30 January 2018 – API set 1.7 – this bug is still there!**

The JS can correctly read these large numbers – it just silently gets the wrong answer when writing them back.

I ran 5 tests:

- 9876543210 – a large integer
- 9876543210.0 – a large double that can convert to an integer
- 9876543210.1 – a large non-integer double
- ‘9876543210’ – a large number as a string
- “‘9876543210” – a large number as a string prefixed with ‘

The results were:

- 1286608618 – wrong
- 1286608618 – wrong
- 9876543210.1 – correct
- 9876543210 – gives a number but the string type has been ignored by Excel
- ‘9876543210 – correct – Excel treats this as string because of the ‘

Here is the test code:

async function run() { try { await Excel.run(async (context) => { let sheet = context.workbook.worksheets.getActiveWorksheet(); let rng1 = sheet.getRange("A3"); rng1.values = [[9876543210]]; let rng2 = sheet.getRange("A5"); rng2.values = [[9876543210.0]]; let rng3 = sheet.getRange("A7"); rng3.values = [[9876543210.1]]; let rng4 = sheet.getRange("A9"); rng4.values = [['9876543210']]; let rng5 = sheet.getRange("A11"); rng5.values = [["'9876543210"]]; await context.sync(); }); } catch (error) { OfficeHelpers.Utilities.log(error); } }

The real problem of course comes when you use JS to read a range and write it back but you don’t know what the range contains. **If it’s a large integer your code is FUBAR.**

The only current bypass is to loop through the range values, test for large integers and convert them to string by surrounding with ‘.

**I sure hope this gets fixed soon!**

async function setValue() { try { await Excel.run(async (context) => { let sheet = context.workbook.worksheets.getActiveWorksheet(); let rng1 = sheet.getRange("A1:A2").load("values"); await context.sync(); let rng2 = sheet.getRange("B4:b5"); let rng3 = sheet.getRange("B6:B7"); rng2.values = rng1.values; rng3.values = rng1.values; rng2.values[0][0] = rng2.values[0][0] + 0.9; rng3.values[0][0] = rng3.values[0][0] + 0.01; await context.sync(); }); console.log("Done!"); } catch (error) { OfficeHelpers.Utilities.log(error); } }

**Well this does not work: both B4 and B6 have 0.91 added to them: wrong answer!**

The reason this does not work is that JavaScript does something called **“shallow copying”** for objects and arrays. In effect this means that rng2 and rng3 are just different names for rng1: they all refer to the same set of values.

**So when you change one variable you are actually changing them all!**

A “Deep Copy” is one where the values really are copied rather than just adding an extra name for the values. JQuery has a handy method for doing this: JQuery.extend ($ is short for JQuery)

// create deep copy of rng1 let deep1 = []; $.extend(true, deep1, rng1.values); // set rng2 = deep copy rng2.values = deep1;

So now I can assign the deep copy to rng2.

**But if I also assign the same deep copy to rng3 I am back in the same trap: rng2 and rng3 would just be different names for the deep copy!**

So I need to either create another deep copy to use for rng3 or assign rng1 to rng3.

Of course then when I change rng3 I am also changing rng1 but that does not matter (although probably bad practice) because I am not returning rng1 back to the worksheet.

(rng1 never appears on the left of the = assignment)

async function setValue() { try { await Excel.run(async (context) => { let sheet = context.workbook.worksheets.getActiveWorksheet(); let rng1 = sheet.getRange("A1:A2").load("values"); await context.sync(); // create deep copy of rng1 let deep1 = []; $.extend(true, deep1, rng1.values); let rng2 = sheet.getRange("B4:b5"); let rng3 = sheet.getRange("B6:B7"); // set rng2 = deep copy rng2.values = deep1; // set rng3 = rng1 rng3.values = rng1.values; rng2.values[0][0] = rng2.values[0][0] + 0.9; rng3.values[0][0] = rng3.values[0][0] + 0.01; await context.sync(); }); console.log("Done!"); } catch (error) { OfficeHelpers.Utilities.log(error); } }

Shallow copies are a wonderful JavaScript “Gotcha” for VBA programmers!

]]>JavaScript has some powerful array methods so I wanted to see how they performed compared to VBA. I looked at four different ways of processing data using the JS API:

- Get data into a JavaScript Array and loop
- Get data into a JavaScript proxy Range object and loop
- Get data into a JavaScript array and use the JS Reduce method
- Call the worksheet function COUNTIFS from JavaScript

I am using the same test data as the previous post: 100000 rows with 2 columns.

Column A is randomly 50% populated with “X” and Column B is randomly 50% populated with “Y”.

The task is to count how many rows have an “X” in column A and a “Y” in column B in the same row.

This task is much slower than VBA: JavaScript takes around 290 milliseconds to read 100000 rows and 2 columns, but VBA takes only around 16 milliseconds.

Let’s ignore that and just focus on how efficient JavaScript is at processing arrays.

If you ignore the time taken to get the data into the array then **JavaScript and VBA are equally efficient** – 19 milliseconds each.

I expected it to be faster to process the proxy range object directly rather than copying the data into an array and using that – but I was wrong. **Looping directly on the proxy object is a lot slower than looping on an array derived from the proxy object.**

Similarly I thought that the array Reduce method would be fast: **but Reduce is slower than directly looping the array!**

**The overall winner in this case is COUNTIFS** because the data never gets transferred to VBA or JavaScript so the extra 290 (JS) or 16 (VBA) milliseconds don’t get incurred. Calling a worksheet function from **VBA also has a much smaller overhead than calling it from JS.**

Here are the four different examples of the JavaScript code.

The complete JavaScript code I am using for the looping the array method looks like this:

var t0; var t1; var t2; $('#run').click(function () { t0 = performance.now(); invokeRun() .then(() => { t2 = performance.now(); console.log("Time to read data from XL " + Math.round(t1 - t0) + " milliseconds.") console.log("Time to process array " + Math.round(t2 - t1) + " milliseconds.") }) .catch(OfficeHelpers.logError); }); function invokeRun() { return Excel.run(function (context) { var range1 = context.workbook.worksheets.getItem("Sheet1").getRange("A1:B100000").load('values'); return context.sync() .then(() => { var arr = range1.values; t1 = performance.now(); var nFound = 0; for (var j = 0; j < arr.length; j++) { if (arr[j][0] === 'X') { if (arr[j][1] === 'Y') nFound++; }; }; console.log("XY pairs found " + nFound); }) }); }

The invokeRun function loads the values from the range into a proxy range object using context.sync() , then creates a JavaScript array (actually an array of arrays) from the proxy object and loops down the array looking for an X and a Y in the same row.

function invokeRun() { return Excel.run(function (context) { var range1 = context.workbook.worksheets.getItem("Sheet1").getRange("A1:B100000").load('values'); return context.sync() .then(() => { t1=performance.now(); var nFound = 0; for (var j = 0; j < range1.values.length; j++) { if (range1.values[j][0] === 'X') { if (range1.values[j][1] === 'Y') nFound++; }; }; console.log(nFound); }) }); }

This version of InvokeRun loops directly on the proxy object values rather than on an array derived from the proxy object.

This version of InvokeRun uses JavaScript’s REDUCE array method, where you supply an aggregating function to be applied to each row of the array.

function invokeRun() { return Excel.run(function (context) { var range1 = context.workbook.worksheets.getItem("Sheet1").getRange("A1:B100000").load('values'); return context.sync() .then(() => { t1 = performance.now(); var arr = range1.values; var nFound = arr.reduce(function (ct, currval, ix, arr) { if (arr[ix][0] === 'X') { if (arr[ix][1] === 'Y') { ct++; } } return ct; }, 0); console.log(nFound); }) }); }

This version demonstrates calling a worksheet function on the range. Since the range values never get passed across to JavaScript it is by far the fastest solution for this case!

function invokeRun() { return Excel.run(function (context) { var rangeA = context.workbook.worksheets.getItem("Sheet1").getRange("A1:A100000"); var rangeB = context.workbook.worksheets.getItem("Sheet1").getRange("B1:B100000"); var count = context.workbook.functions.countIfs(rangeA, "X", rangeB, "Y"); count.load(); return context.sync() .then(() => { t1 = performance.now(); console.log("XY pairs found " + count.value); }) }); }

For completeness sake here is the equivalent VBA code for the looping the array case.

Sub FindXY3() Dim vArr As Variant Dim j As Long Dim n As Long Dim dTime As Double Dim dTime2 As Double dTime2 = MicroTimer vArr = Range("a1:B100000").Value2 dTime = MicroTimer For j = LBound(vArr) To UBound(vArr) If vArr(j, 1) = "X" Then If vArr(j, 2) = "Y" Then n = n + 1 End If End If Next j Debug.Print "Var array " & n & " Get " & (dTime - dTime2) * 1000 & " Find " & (MicroTimer - dTime) * 1000 End Sub

**JavaScript seems fairly efficient at processing arrays, and is very comparable to VBA.**

**The problem is the time taken to transfer data from Excel to JavaScript.**

**Of the JavaScript array methods bench-marked, Reduce and direct processing of the proxy object were slower than direct looping on an array.**

**Using a worksheet function such as COUNTIFS is considerably faster than looping an array as long as you can avoid transferring the data to VBA or JavaScript.**

]]>