Pivot Data by Weekday

[JB86]

Hello! I am trying to either unpivot or pivot my data from the top format into the bottom format in order to calculate percent difference week over week. Thank you!

[JB86]

Sure thing

Week Of	day_abbrev	Service Level
9/4/2022	Mon	0.98
9/4/2022	Tues	0.86
9/4/2022	Wed	0.85
9/4/2022	Thurs	0.84
9/4/2022	Fri	0.77
9/25/2022	Mon	0.51
9/25/2022	Tues	0.94
9/25/2022	Wed	0.91
9/25/2022	Thurs	0.91
9/25/2022	Fri	0.92
9/18/2022	Mon	0.64
9/18/2022	Tues	0.86
9/18/2022	Wed	0.77
9/18/2022	Thurs	0.9
9/18/2022	Fri	0.7

[ronrsnfld]

Hopefully I've understood what you want, as you do not show the desired results based on the source data.

I assume you want the percent change for each weekdays Service Level.

Read the comments and explore the Applied Steps to understand the algorithm:

Original Data

let
    
//change next line to reflect your actual data source
    Source = Excel.CurrentWorkbook(){[Name="Table9"]}[Content],

//set correct data types
    #"Changed Type" = Table.TransformColumnTypes(Source,{
        {"Week Of", type date}, 
        {"day_abbrev", type text}, 
        {"Service Level", type number}
        }),

//Sort by Week Of, Descending
    #"Sorted Rows" = Table.Sort(#"Changed Type",{{"Week Of", Order.Descending}}),

//Group by Weekday
//   Generate List of percent changes based on week to week change
//   Return Week Of Date and Percent change columns
    #"Grouped Rows" = Table.Group(#"Sorted Rows", {"day_abbrev"}, {
        {"Change", (t)=>
            Table.FromColumns({t[Week Of]} & 
        {List.Generate(
            ()=>[d=(t[Service Level]{0} - t[Service Level]{1}) / t[Service Level]{1}, idx=0],
            each [idx] < (Table.RowCount(t)),
            each [d=try (t[Service Level]{[idx]+1} - t[Service Level]{[idx]+2}) / t[Service Level]{[idx]+2} otherwise null, idx=[idx]+1],
            each [d])}),
            type table[Column1=date, Column2=Percentage.Type]}
    }),
    #"Expanded Percent Change" = Table.ExpandTableColumn(#"Grouped Rows", "Change", 
        {"Column1", "Column2"},{"Week Of", "Percent Change"}),

//Pivot on Week Of, with no aggregaton
    #"Pivoted Column" = Table.Pivot(Table.TransformColumnTypes(#"Expanded Percent Change", 
        {{"Week Of", type text}}, "en-US"), 
        List.Distinct(Table.TransformColumnTypes(#"Expanded Percent Change", 
            {{"Week Of", type text}}, "en-US")[#"Week Of"]), "Week Of", "Percent Change"),
    
//add day number column for sorting
// then sort by day number and remove that column
    #"Added Custom" = Table.AddColumn(#"Pivoted Column", "day number", 
        each List.PositionOf({"Mon","Tues","Wed","Thurs","Fri"},[day_abbrev])),
    #"Sorted Rows1" = Table.Sort(#"Added Custom",{{"day number", Order.Ascending}}),
    #"Removed Columns" = Table.RemoveColumns(#"Sorted Rows1",{"day number"})
in
    #"Removed Columns"

Results

[ronrsnfld]

It would be helpful if you posted your source data as text which can be copy/pasted, rather than as a screenshot.