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Duffkess Regular Visitor
Regular Visitor

Datasource CSV File Folder > Delete old Data creates expression.error

Hi There,

 

I have 2 different Folders with CSV Files for every day.

 

Folder A

> A-2017-01-01

> A-2017-01-02

Folder B

> B-2017-01-01

> B-2017-01-02

 

This files in each folder are merged together and have a relation between folder A and folder B, everything is working fine.

 

But the files are created everyday and I only need the last 2 weeks.

 

So I thought I could delete the old csv files which are not needed anymore.

 

But when I do that is says :

 

expression.error the key didn't match any rows in the table

 

But for me it looks like its searching for entrys that are used to be in the old csv files but I just want it do forget about the old csv files.

 

Is this somehow possible?

 

Thank you in advance.

4 REPLIES 4
MarcelBeug Super Contributor
Super Contributor

Re: Datasource CSV File Folder > Delete old Data creates expression.error

Probably the name of an old file is hard coded in one of your queries. Prime suspect would be a query "Sample Binary", which is one of the objects created when the "Combine Binaries" functionality is used to combine files from a folder.

 

You can adjust that code so it points to the first (selected) file in the folder.

For instance:
SampleBinary = Source{0}[Content]

where "Source" is the name of the previous step.

 

This behaviour was adjusted (for new combine binaries) in the May 2017 upgrade, as follow up on an idea raised by yours truly.

Specializing in Power Query Formula Language (M)
Duffkess Regular Visitor
Regular Visitor

Re: Datasource CSV File Folder > Delete old Data creates expression.error

Hi MarcelBeug,

 

sorry for the late reply.

 

My "SampleFile" looks like this in advanced editor (german, Quelle = source):

 

let
    Quelle = Folder.Files("C:\perfdata"),
    #"C:\perfdata\_perfdata_2017-04-05 csv1" = Quelle{[#"Folder Path"="C:\perfdata\",Name="perfdata_2017-04-05.csv"]}[Content]
in
    #"C:\perfdata\_perfdata_2017-04-05 csv1"

But I dont have any other previous step, so how should I do this here?

 

Thanks for any hint!

MarcelBeug Super Contributor
Super Contributor

Re: Datasource CSV File Folder > Delete old Data creates expression.error

So "Quelle" is your previous step and the solution would:

 

let
    Quelle = Folder.Files("C:\perfdata"),
    SampleBinary = Quelle{0}[Content]
in
    SampleBinary
Specializing in Power Query Formula Language (M)
CahabaData New Contributor
New Contributor

Re: Datasource CSV File Folder > Delete old Data creates expression.error

This interests me.  Let me see if I understand your issue generically: your source file(s) name(s) is/are regularly changing (we assume the structure is always identical)... 

 

and so are you invoking the Refresh or are you changing data source and doing a new Get Data?

 

 

www.CahabaData.com

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