Unpivot and append dynamically multiple columns

[jimmybi]

Hi guys,

I need a bit of Power Query magic. I have data from Excel files that has data for around many devices with time stamp. It looks something like this:

Timestamp    DeviceName EmptyColumn Timestamp1 ....

Unix time       Numbers        Nulll                Unix time

When I convert the Timestamp to Date/Time it works perfectly. And every Timestamp column has exactly the same value. So I need only 1 Timestamp column. What I need to do next is to unpivot the Device Name column so I would have it as a value next to the Timestamp and the numbers next to it. Essentially I need to have only 3 Columns: Timestamp with the time, Device Name with the list of the device names and the numbers collerating to the device on the 3rd column. Now I know that this can be done with unpivoting the columns. But I have 456 columns with every 3rd being empty. I also need to append the values after unpivoting them and this should be done dinamically (I really don't want to do this manually).

So far I have found that you can make something with List.Alternate, but I don't know how to append them, and how exactly it works. Any thoughts?

Thanks!

Jimmy 

[v-cherch-msft]

Hi @jimmybi

You may try to do it in Advanced Editor. Here are some references for you.

https://www.oraylis.de/blog/power-query-how-to-unpivot-a-dynamic-number-of-columns

https://wessexbi.wordpress.com/2014/02/27/unpivot-nested-headings-with-power-query/

Regards,

Cherie

[jimmybi]

Hi Cherie,

I saw those links and they are useful. That is where I got the List.Alternate idea from. However since I am using a folder as a source it gives me the folder column names. I tried to use them in the Advanced editor for the sample file and this is what I get: 

Edit Queries Snapshot

And this is my M code:

So my problem is where to get the list from at the moment. Any ideas?