我想创建一个额外的列到我的数据集。 这需要通过在PowerQuery基于M来完成。 我有weeknumber，dayoftheweek和年使用。
这可以通过使用Excel中的下列公式来完成。 我需要M.类似的东西，但随后
Date = DATE([year],1,-2)-WEEKDAY(DATE([year],1,3))+[week]*7 + [day]-1
例如：第2周，第3天，2019年应该是：2019年9月1日（在＃DD-MM-YYYY＃）
提前致谢
Answer 1:
这将做到这一点
= Table.AddColumn(Source, "Custom", each Date.From(Number.From(Date.AddDays(Date.FromText("1/1/"&Number.ToText([year])),-3))-Date.DayOfWeek(Date.FromText("1/3/"&Number.ToText([year])))-1+[week]*7+[day]-1) )
Answer 2:
如果你想创建自己的功能，它可能是这样的：
dateFromWeekDayYear = (WeekOfYear as number, DayOfWeek as number, Year as number) as date =>
let
endOfFirstWeekOfYear = Date.EndOfWeek(#date(Year, 1, 1), Day.Monday), // Consumes one week from "WeekOfYear"
addRemainingWeeks = Date.AddWeeks(endOfFirstWeekOfYear, WeekOfYear - 2), // Subtract 2 because consumed one week above and because 0-based
addDays = Date.AddDays(addRemainingWeeks, DayOfWeek) // Don't need to make 0-based as previous step gives us end of prior week.
in
addDays,
它有三个参数：今年周，周和年（基本上你有资料）的日子。
如果你想将其添加到一个表，你可以尝试这样的：
Table.AddColumn(someTable, "newColumnName", each dateFromWeekDayYear([weekColumn], [dayColumn], [yearColumn]))
（前提是你的表someTable载列weekColumn ， dayColumn ， yearColumn ）。
文章来源: Get date from weeknumber, dayofweek and year PowerQuery M
