Rolling calender in Power BI

[IhabSan]

I get this erroe when I am trying to type this code "Expression.Error: The name Source was not recognized. Check that it is spelled correctly."

= List.Dates (Source, Number.From(DateTime.LocalNow()) - Number.From(Source), #duration(1,0,0,0))

I tried many times with source but does not work
=#date(2015, 1, 1)
=#date(2015-1-1)
=#date(2015/ 1/ 1)

 

[jdellasala]

The syntax for List.Dates is

List.Dates( start as date, count as number, step as duration) as list

for example:

List.Dates(#date(2011, 12, 31), 5, #duration(1, 0, 0, 0))

That will result in a list of Dates from 12/31/2011 to 01/04/2012. If you load the list to a table or convert it to a table, the values in the table will be numbers like 40908 for 12/31/2011, but will show correctly as dates when formatted as Date.
The above comes from the Power Query M formula language. A link to download the PDF is at the bottom left of the page.