Extracting multiple date formats from text column in Power query

[isa2003]

Hello:

I have a text column within which the date can be found. However, the format of the date varies from yyyy-MM-dd, yyyy/MM/d, dd/MM/yyyy, MM-yyyy, yyyy etc. How can only the date be extracted from the column into a new column?  I am interested only in the year.  e.g. 
Liz Coleman Online 12/12/2017 Notebooks Pencils
Candy Shanner-Mail 09/2009- Folders

Thanks in advance. 

[ronrsnfld · Accepted solution]

You split the date string by various delimiters, and select the one with four digits: (if you have additional delimiters, edit the Text.SplitAny function accordingly.

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMjIwMtE1MNU1MFKK1YFw9Q1M9SE8AyMwGygG4ZrqwtkQRiwA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Date = _t]),
    
//Type "Date" as text
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Date", type text}}),

//year will be the segment with four digits
    #"Add Year" = Table.AddColumn(#"Changed Type","Year",(r)=>
        List.Select(Text.SplitAny(r[Date],"-/"), each Text.Length(_)=4){0}, Int64.Type)
in
    #"Add Year"