Power Query Free Training Webinar Follow-Up Questions

17 April, 2015 (10:00) | M, Power Query, Professional Development | By: Mark V

On April 7th, I gave my Power Query: Data Chemistry for the Masses presentation as part of Pragmatic Works Free Training on the T’s series. You can find the recording of that webinar here. I want to take a moment to thank the folks at Pragmatic Works for organizing and hosting this series that is such a great asset to the community.

At the end of the session, there were more questions than we had time to handle. So, they emailed me the questions in order for me to answer them in a post like this. Behold!

What is the maximum number of rows allowed in an Excel worksheet?

This question was likely in response to my recommendation of loading Power Query results to the Excel Data Model (Power Pivot) instead of to a worksheet. According to this info from Microsoft, the maximum row count in a worksheet is 1,048,576.

When combining files in a folder can the workbook have multiple tabs?

As far as combining files using the From Folder source, I have only succeeded with text files. However, there is a post here on the Dutch Data Dude blog that explains how to combine that source with a little custom M to make this happen.

When passing a parameter to an M function, can you select from a pick list of choices?

This question was in response to my converting a power query on Nobel Prize Laureates into a function that prompts for a prize category and then returns the Laureates for that category. Typically, instead of users interacting directly with the function, the parameter is passed to the function via a custom column. There is great post here on the Data Chix blog on how to do this.

Could we get a copy of the file being used in the demo?

You can get all of the materials for the presentation, including the files used, on the page for that presentation on this very blog.

Is the option to load to data model available for Excel 2010 or later versions?

I just learned over the weekend at SQL Saturday Madison that Excel 2010 does NOT have the option to load directly to the Data Model. Bummer. So, if you are using Excel 2010, you will need to load to a worksheet and then import to Power Pivot from that worksheet.

How do you know a web page is in JSON?

Well, web pages are not really in JSON. JSON is actually a “lightweight document interchange format.” I think of it more like a simpler XML. This question comes from my use of the Nobel Prize API to download Laureate data in the JSON format as part of this presentation. This is also detailed here as part of my Power Query Decathlon – Beginner blog series. The URL for consuming the API using JSON is http://api.nobelprize.org/v1/laureate.json. You can also do it as a CSV using http://api.nobelprize.org/v1/laureate.csv which will actively download a CSV file with all of the same data.

What do the different separators mean? [] i guess means column, but what is {} for?

I assume this question is related to the appearance of [] and {} in M query syntax. You can read about these in the Query Formula Language Specification document. This is a large resource and not recommended for “light” reading. :) According to the specification, “We can use the lookup operator ([]) to access the fields of a record by name.” Also, the brackets [] can be used for referring to Records by surrounding the elements within the Record. the {} curly braces are used to referring to a List. A great, and easy to follow, resource is Chris Webb’s great book Power Query for Power BI and Excel. I am still very much a student of M, so I will not go much deeper into this at the moment.

Any plan from MS to add the ability to export the resulting data to a place other than XL, Data Model, eg text file, db?

I would LOVE the ability to use Power Query to load data into a database or a file, etc. Note that Power Query is used outside of Excel for loading data in the new Power BI preview as well as the Power BI Designer, which is also currently in preview. I have yet to see public information regarding any detailed plans for using Power Query to load to a larger number of targets. However, given the investment Microsoft is making in Power Query, it seems likely to me that we will see it popping up in more places in the future.

Could we use an Itunes folder as a source and consolidate music metadata?

Yup.

Here is the M code for a query I used to do just that:

let
    Source = Folder.Files("C:\Users\Mark\Music\iTunes\iTunes Media\Music"),
    #"Removed Other Columns" = Table.SelectColumns(Source,{"Name", "Folder Path"}),
    #"Replaced Value" = Table.ReplaceValue(#"Removed Other Columns","C:\Users\Mark\Music\iTunes\iTunes Media\Music\","",Replacer.ReplaceText,{"Folder Path"}),
    #"Split Column by Delimiter" = Table.SplitColumn(#"Replaced Value","Folder Path",Splitter.SplitTextByEachDelimiter({"\"}, null, false),{"Folder Path.1", "Folder Path.2"}),
    #"Changed Type" = Table.TransformColumnTypes(#"Split Column by Delimiter",{{"Folder Path.1", type text}, {"Folder Path.2", type text}}),
    #"Replaced Value1" = Table.ReplaceValue(#"Changed Type","\","",Replacer.ReplaceText,{"Folder Path.2"}),
    #"Split Column by Position" = Table.SplitColumn(#"Replaced Value1","Name",Splitter.SplitTextByPositions({0, 2}, false),{"Name.1", "Name.2"}),
    #"Changed Type1" = Table.TransformColumnTypes(#"Split Column by Position",{{"Name.1", Int64.Type}, {"Name.2", type text}}),
    #"Split Column by Delimiter1" = Table.SplitColumn(#"Changed Type1","Name.2",Splitter.SplitTextByEachDelimiter({"."}, null, false),{"Name.2.1", "Name.2.2"}),
    #"Changed Type2" = Table.TransformColumnTypes(#"Split Column by Delimiter1",{{"Name.2.1", type text}, {"Name.2.2", type text}}),
    #"Renamed Columns" = Table.RenameColumns(#"Changed Type2",{{"Name.1", "Track"}, {"Name.2.1", "Song"}, {"Name.2.2", "File Type"}, {"Folder Path.1", "Artist"}, {"Folder Path.2", "Album"}})
in
    #"Renamed Columns"

In the Code above, I highlighted the path to my Itunes folder. Just replace that with yours and past into a blank Power Query window. Here is the query once you have done so.

image

There is more data in the Itunes Music Library.xml file, but I haven’t figured out how to use it effectively yet.

Alright. That wraps up the questions. Thanks to all who tuned in to the webinar and provided such great questions.

Write a comment