Excel

List.SelectPositions in Power BI and Power Query

by

With this new custom function “List.SelectPositions” you can easily select items from a list by just passing a list of their positions within it as the parameter.

What it does

Say you have a list with numbers {1..5} and want to select the 1st, 4th and 5th element from it. Then you can pass these positions to the function as another list: {0, 3, 4}.

ListSelectPositions({1..5}, {0, 3, 4}) will return: {1,4,5}

You see that I’ve decided to follow the zero-based counting principle here, that you find throughout M in the query editor. If you don’t like that, you can use the optional 3rd parameter to let it start to count from 1 instead:

ListSelectPositions({1..5}, {1, 4, 5}, 1) will return {1, 4, 5}

But if you have entered positions that don’t exist, the function will return an error in their positions by default:

ListSelectPositions({1..5}, {1, 4, 5}) will return {2, 5, Error}

because there is no 6th element (you’ve omitted the 3rd parameter that allows you to start counting with 1).

But you can change this behaviour as well through the last optional 4th parameter: Setting it to 0 will fill the missing positions with null like this:

ListSelectPositions({1..5}, {1, 4, 5}, null, 0) will return {2, 5, null}

and setting it to 1 will eliminate it and shorten the list like this:

ListSelectPositions({1..5}, {1, 4, 5}, null, 1) will return {2, 5}

These additional error-handling-options of the 4th parameters are useful for dealing with badly formatted data and if you want to learn more about it, just let me know in the comments so that I can prioritize it.

Function code

Read more

Table.Group: Exploring the 5th element in Power BI and Power Query

by

In this post I’ll show you the magic stuff you can do with the 5th parameter (the optional comparer function) of the Table.Group M-function in Power BI and Power Query:

Table.Group parameters

  1. table as table,
  2. key as any,
  3. aggregatedColumns as list,
  4. optional groupKind as nullable number,
  5. optional comparer as nullable function

If you’re not familiar with the 4th parameter (groupKind) already, I strongly recommend to read Chris Webb’s article, as we will build on its knowledge here.

Another aspect worth mentioning for the modus in GroupKind.local is the performance aspect: It runs MUCH faster for large datasets than the default-setting. So if you are sure that your data will always be sorted accordingly, you can speed up your grouping-operations considerably. That means: Your data has to be sorted correctly by default. At least for my tests, you would loose the performance-gain once you’d sort your table by an explicit step before.

You can find an overview of comparer functions here.

Case insensitive grouping

Imagine there was a twist in Chris’ dataset and it would look like so:

Table.Group – Modified Source Data

We would probably not be happy with these results then:

Table.Group Problem with Case Sensitivity

Because M is by default case sensitive, we get more groups than we want. Let’s try Comparer.OrdinalIgnoreCase to the rescue then:

Pretty neat, isn’t it 😉  (You can use that comparer in other functions as well, see here for text- and list operations)

Something like this was what I’ve showed Huang Caiguang the other day, who asked me what the 5th parameter of this function was about (or so I understood). He then sent me a link to one of his articles, which demanded a good 2 hours for me to digest and understand: We can also use custom functions to create all different sorts of grouping behaviours here. These are my 2 favourites:

Read more

Date.DatesBetween to retrieve dates between 2 dates in Power BI and Power Query

by

Today I’m sharing a handy function with you that allows you to retrieve all or just a couple of dates between 2 given dates: Date.DatesBetween.

Usage

This function takes 3 parameters:

  1. From- or Start-date
  2. To- or End-date
  3. A selection of ONE of these intervals: Year, Quarter, Month, Week or Day

All dates will be created at the end of the chosen interval: So if you want to analyse events with a duration for example, where you want to transform your data to show one day per (monthly) event, this function generates month-end-dates for every month within the timespan. Please not that if the To-/End-date is within a month, the last element of the list will NOT be that day, but the day of the end of that month.

The default-value for the 3rd parameter is “Day”, so if you omit the specification, the function will return a list of all days in between.

Read more

How Power Query can return clickable hyperlinks with friendly names to Excel

by

When you use Power Query as an Excel-automation-tool rather than just to feed the data model, you might want to return clickable hyperlinks that carry friendly names. This doesn’t work out of the box, but with a little tweak it will be fine:

The trick

Return a text-string that contains the Excel (!)-formula for hyperlinks, preceded by an apostrophe  ‘ . After the data has been loaded to the sheet, check the column and replace ‘= by = to activate your Excel-formula:

Activate the HYPERLINK formula by replacing ‘= with =

You can then format the column to “Hyperlink”:

Read more

How to open a complex JSON record in Power BI and Power Query

by

Today I’ll show you a very useful technique how to deal with a JSON record that contains a wild mixture of different elements like this: If you click on one of the expandable elements, their content will be shown, but you’ll loose all the “surrounding” information (metadata) that is visible now. This is often an … Read more

How to import from Excel with cell coordinates in Power Query and Power BI

by

There might be occasions where you want to import data from Excel into Power Query or Power BI using cell coordinates like a range from E3 until G9 for example (“A1 cell reference style”). The function I provide below also caters for the potential pitfalls of this task that Maxim Zelensky has described in his article.

Background

If your worksheet has one leading empty row and column, the import will ignore them and automatically return the range starting from B2. So to fetch the range E3:G9 you have to delete the first row and the first 3 columns. But as Maxim has found out, remaining formats on empty cells will lead to an import of empty rows and columns. So the number of rows and columns to delete will vary and is hard/impossible to predict.

Method

The range that PowerQuery or PowerBI will import is stored in the Excel-file already in the sheet-data and the xml looks like this (“Sample3” from Maxims data):

The imported range is E1 till J12, as the first rows contain formatting instructions, and will therefore be imported as well. In the 3rd row E3 shows up with the first value, which is surrounded by “<v>”.

This is how it looks like in the Xml.Table in the query editor:

Task is to calculate the number of rows and columns delete, considering the individual offset that is caused by the formatted empty cells.

Code

So I’ve cooked together these ingredients in a pretty massive code that you can download here: fnImportFromExcelCellCoordinates.txt

How to use the function

Read more