ImkeF

let func =  
 (function as function) =>
let
function_ = function,

Metadata = (functionType) as record =>
    let
        Help = Value.Metadata(if functionType is type then functionType else Value.Type(functionType))
    in
        Help,

ImkeF

let func =  
 (SourceTable as table, TermColumn as text, UntilTerm, optional KeepOrDrop, optional IgnoreCase) =>
let
    Source = SourceTable,
    Column = TermColumn,
    UntilTerm = UntilTerm,
    CaseSensitivity = if IgnoreCase = null then 0 else IgnoreCase,
    Position = if List.Contains({"Yes",1}, CaseSensitivity) 
     then List.PositionOf(Table.Column(Source, Column), UntilTerm, Occurrence.First, Comparer.OrdinalIgnoreCase) 
     else List.PositionOf(Table.Column(Source, Column), UntilTerm),

ImkeF

let func =  
(SelectionList as list, ListOfPositions as list, optional StartWithOne as number) =>

List.Transform(ListOfPositions, each try if StartWithOne = null then SelectionList{_} else SelectionList{_-1} otherwise null)
, documentation = [
Documentation.Name =  " List.SelectPositions
", Documentation.Description = " Selects items from <code>SelectionList</code> by their positions in <code>ListOfPositions</code>
" , Documentation.LongDescription = " Selects items from <code>SelectionList</code> by their positions in <code>ListOfPositions</code>: https://wp.me/p6lgsG-N8 .
", Documentation.Category = " List
", Documentation.Source = " https://wp.me/p6lgsG-N8 .

ImkeF

let func =  
 (inputList as list, chunkSize as number) =>
let
ListSelectPositions =  (SelectionList as list, ListOfPositions as list) => List.Transform(ListOfPositions, each try SelectionList{_} otherwise null),
    Source = inputList,
    ChunkSize = chunkSize,
    Count = Number.RoundUp(List.Count(Source)/ChunkSize),
    Chunks = {1..Count},
    Positions = List.Transform(Chunks, each {_*ChunkSize-ChunkSize.._*ChunkSize-1}),
    Allocate = List.Transform(Positions, each ListSelectPositions(Source, _))

ImkeF

let func =  
 (SelectionList as list, ListOfPositions as list, optional StartWithOne as number, optional FillWithNulls as number) =>
let

selectionList = List.Buffer(SelectionList),
listOfPositions = ListOfPositions,
StartPosition = if StartWithOne = 1 then -1 else 0,

Result = {List.Transform(listOfPositions, each selectionList{_ + StartPosition}), // null
          List.Transform(listOfPositions, each selectionList{_+StartPosition}?), // 0

ImkeF

let func =  
 (t as table, optional maxSample as number) =>
let

primitiveTypes = (t as table, optional maxSample as number) as table =>
let
Table = t,
MaxSample = maxSample,
Sample = if maxSample = null then Table.FirstN(Table,10) else Table.FirstN(Table,Number.From(maxSample)),
Columns = Table.ToColumns(Sample),

ImkeF

let func =  
 (Value as any) as text =>

    let
        t = Value.Type(Value),

        nonNullableType = Type.NonNullable(t),

        TypeDescription = 
         if Type.Is(nonNullableType, type number) then "number"

ImkeF

let func =  
 (Expression as any, Values as list, Results as list, optional Else as any) =>

try Results{List.PositionOf(Values, Expression)} 
otherwise if Else = null then "Value not found" 
                         else Else
, documentation = [
Documentation.Name =  " M.Switch
", Documentation.Description = " Evaluates an  <code>Expression</code>  against a list of  <code>Values</code>  and returns one or multiple possible  <code>Results</code>  expressions.
" , Documentation.LongDescription = " Evaluates an  <code>Expression</code>  against a list of  <code>Values</code>  and returns one or multiple possible  <code>Results</code>  expressions.

ImkeF

let func =  
 (Table_ as table, newColumn as list, columnName as text) =>
let
    ToColumns = Table.ToColumns(Table_),
    FromColumns = Table.FromColumns(ToColumns&{newColumn}, Table.ColumnNames(Table_)&{columnName})
in
    FromColumns
, documentation = [
Documentation.Name =  " Table.AddColumnT
", Documentation.Description = " Adds a column to a  <code>Table_</code> that originates from a  list holding the values for the  <code>newColumn</code> . New <code>columnName</code>  to be passed as the last argument.

ImkeF

based on https://en.wikipedia.org/wiki/ISO_week_date#Calculating_the_week_number_of_a_given_date

M / Power Query doesn't have a native ISO8601 Week Number function, and DAX's weeknum(x, 21) doesn't give the correct ISO Week-Year.

Date → ISO Week

/*
based on <https://en.wikipedia.org/wiki/ISO_week_date#Calculating_the_week_number_of_a_given_date>