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# Monday Morning Mulling: July 2020 Challenge

3 August 2020

On the final Friday of each month, we set an Excel problem for you to puzzle over for the weekend.  On the Monday, we publish a solution.  If you think there is an alternative answer, feel free to email us.  We’ll feel free to ignore you.

Welcome to this month’s Monday Morning Mulling.  Our solution to this month’s challenge uses a function most of you never even have considered, or perhaps didn’t even know existed…

The Challenge

“All” I wanted to do was be able to take a text string and split it up so that each element of text was split into a separate column formulaically, e.g.

Note I have used different separators (delimiters) in the two examples displayed. The fact I have used four elements each time is entirely coincidental.

As usual, please feel free to refer to the associated Excel file to see how our solution works.

Suggested Solution

It’s not impossible to come up with some monstrous calculation using a combination of text functions.  Some of you may have worked out some horrendous formula that appears to work.  I applaud you if you have.

For the formula in cell G13:

=TRANSPOSE(FILTERXML("<x><y>"&SUBSTITUTE(E13,",","</y><y>")&"</y></x>","//y"))

Er, what the..?

Maybe this needs some explanation.  Let’s start with the highly popular and frequently used FILTERXML function.  Hands up all those who use this function regularly…

The FILTERXML function

Until Excel 2013, Excel was mostly an offline application, although you could use VBA, Power Query / Get & Transform or Power Pivot in Excel to gain access to internet and online datasets.  However, Excel 2013 changed all that and introduced two new functions to the world:

1. WEBSERVICE, which provides immediate and easy access to any REST WebAPI assuming you have an internet connection by downloading the HTTP response of the provided URL;  and
2. FILTERXML, which parses an XML string (i.e. a text string that contains an XML document) and returns a single element (known as a node or attribute) provided by an XPath.  In case you are wondering, XPath is a query language for selecting XML elements such as nodes and attributes and works with both XML and HTML.

Therefore, FILTERXML tends to work in tandem with WEBSERVICE insofar that it makes sense of the long text string delivered by the former function and finds what you are looking for in that text string.

The FILTERXML function employs the following syntax to operate:

FILTERXML(xml, xpath)

The FILTERXML function has the following arguments:

• xml: this is required and represents a string in a valid XML format
• xpath: this is also required. This represents a string in a standard XPath format.

It should be noted that:

• if xml is not valid, FILTERXML returns the #VALUE! error value
• if xml contains a namespace with a prefix that is not valid, FILTERXML returns the #VALUE! error
• the FILTERXML function is not available in Excel Online
•  the FILTERXML function is not available in Excel (2016) for Mac
• Further, this function may appear in the function gallery in Excel for Mac, but it relies on features of the Windows operating system, so it will not return results on a Mac.

Here are some examples:

OK, so far so good.  But there is another function used…

The SUBSTITUTE function

The SUBSTITUTE function, like the REPLACE function, replaces existing text with new text in text strings.  It uses the following syntax to operate:

SUBSTITUTE(text, old_text, new_text, instance_number)

where:

• the text parameter is the string of text that contains the characters that we want to substitute
• the old_text parameter is the string of text that we want the function to look for in the text parameter
• the new_text parameter is the text string that is going to replace the old_text
• the instance_number is the instance which we want the old_text to be replaced by the new_text parameter if there are multiple old_text strings found.  If excluded, all occurrences are replaced.

It is a simple to understand function.

Returning to Our Suggested Solution

Revisiting our example:

For the formula in cell G13:

=TRANSPOSE(FILTERXML("<x><y>"&SUBSTITUTE(E13,",","</y><y>")&"</y></x>","//y"))

Let’s review the first argument of FILTERXML for cell G13:

"<x><y>"&SUBSTITUTE(E13,",","</y><y>")&"</y></x>"

If we calculated this, we would get

<x><y>alpha</y><y>beta</y><y>gamma</y><y>delta</y></x>

Oh now, it’s completely clear (!).

Do you see that the text alpha,beta,gamma,delta has had the comma substituted for </y><y>, and then this has been “wrapped” inside

<x><y>…</y></x>

If you are familiar with XML or even HTML, you might be starting to see where this is all going.  Consider these angular bracket elements:

• <x> and </x> denote the start and end of the data x (you can replace x with pretty much any text string)
• <y> and </y> denote the start and end of a y “node”, i.e. a building block of XML.  Again, you can change y to an alternative annotation.  The overarching idea is that an entire document is a document node; every element in a documane is an element node; text in an element is a text node, etc.  We have y nodes!

Therefore, we have broken the text string up into its text nodes.  Therefore,

=FILTERXML(expression, “//y”)

means parse (split up) each y node.  This will provide a list of the y nodes.  If you are using a version of Excel that supports >dynamic arrays, you would get the following:

Wrapping this function in TRANSPOSE swaps rows to columns and vice versa.  The associated Excel file also demonstrates how this could be performed using “legacy” Excel where dynamic arrays are not recognised by selecting several cells once you have created the formula and pressing CTRL + SHIFT + ENTER.

It’s a little different, but this month shows you how sometimes you can use functions meant for something else completely and use them in an entirely different environment.  We doubt anyone at Redmond envisaged this trick back when this function was coded!

Until next month.

The Final Friday Fix will return on Friday 28 August with a new Excel Challenge.  In the meantime, please look out for the Daily Excel Tip on our home page and watch out for a new blog every business workday.