Combine multiple CSV files, then add IsLatest column based on date in filename in Power Query / M

[hymieho]

I am importing a series of CSV file and they all have a date in the file name.  Ex:

2017-09-26.CSV

2017-10-23.CSV

etc.

I am able to combine them and create a date column based on the filename. Now I would like to add a column called [IsLatest, determine which is the most recent date, and have Yes or No in the column accordingly. I can do this in DAX with a custom column, but I wanted to stretch my M skills but I just can't figure it out. Any Power Query / M gurus who can point me in the right direction?

[v-jiascu-msft · Accepted solution]

Hi @hymieho,

You can try a custom column like this:

List.Max(#"Changed Type"[Column1])

Best Regards,

Dale

[hymieho]

Works like a charm--thanks for the tip!

1. Add a (temporary) custom column as you mentioned with the List.Max(date)

2. Add a 2nd custom column that checks to see if [Date] = [Latest Date in group]

3. Remove the temp column

#"Added Conditional Column" = Table.AddColumn(#"Added Custom", "IsLatest", each if [Add Column with latest date] = [Date] then "Yes" else "No"),
#"Renamed Columns2" = Table.RenameColumns(#"Added Conditional Column",{{"Add Column with latest date", "Latest Date in group"}}),
#"Removed Columns1" = Table.RemoveColumns(#"Renamed Columns2",{"Latest Date in group"})