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lmgibs04's avatar
lmgibs04
Regular Visitor
2 years ago
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Cartesian Product of String Lists in M

 
Hello Everyone, 

 

I'm looking to create a cartesian product of two lists of strings through a function in M. Imagine I have lists {"a","b","c"} and {"1","2","3"} and I want to create a list of lists such that the cartesian product is as follows {{"a1","b1","c1"},{"a2","b2","c2"},{"a3","b3","c3"}}.

 

How could I approach this? 

 

I've considered using a List.Generate but can't seem to get the right arguments that don't return an error. I was also looking at using List.Transform but again couldn't get it to work. 

 

Any help is appreciated. 

 

Thanks!

Need Help
  • Vijay_A_Verma's avatar
    Vijay_A_Verma
    2 years ago

    You may use this

    let
list1 = {"a", "b", "c", "d"},
list2 = {1, 2, 3}
in
List.Split(List.TransformMany(list2, (x)=>list1, (x,y)=> y & Text.From(x)), List.Count(list1))
  • Anonymous's avatar
    Anonymous
    2 years ago

    Hi lmgibs04 ,

    Vijay_A_Verma Good Answer!
    And you can also try this:

     

    let
    List1 = {"a", "b", "c"},
    List2 = {"1", "2", "3"},
    Product = List.Transform(List2, each let currentItem = _ in List.Transform(List1, each _ & currentItem)),
    Result = List.Zip(Product),
    #"Converted to Table" = Table.FromList(Result, Splitter.SplitByNothing(), null, null, ExtraValues.Error),
    #"Extracted Values" = Table.TransformColumns(#"Converted to Table", {"Column1", each Text.Combine(List.Transform(_, Text.From), "#(tab)"), type text}),
    #"Split Column by Delimiter" = Table.SplitColumn(#"Extracted Values", "Column1", Splitter.SplitTextByDelimiter("#(tab)", QuoteStyle.Csv), {"Column1.1", "Column1.2", "Column1.3"}),
    #"Changed Type" = Table.TransformColumnTypes(#"Split Column by Delimiter",{{"Column1.1", type text}, {"Column1.2", type text}, {"Column1.3", type text}})
in
    #"Changed Type"

     

    Just put all of this M function into Advanced Editor, and the final output is as below:


    Best Regards,
    Dino Tao
    If this post helps, then please consider Accept both of our answers as the solution to help the other members find it more quickly.

2 Replies

  • Vijay_A_Verma's avatar
    Vijay_A_Verma
    Icon for Most Valuable Professional rankMost Valuable Professional
    2 years ago

    You may use this

    let
list1 = {"a", "b", "c", "d"},
list2 = {1, 2, 3}
in
List.Split(List.TransformMany(list2, (x)=>list1, (x,y)=> y & Text.From(x)), List.Count(list1))
  • Anonymous's avatar
    Anonymous
    Not applicable
    2 years ago

    Hi lmgibs04 ,

    Vijay_A_Verma Good Answer!
    And you can also try this:

     

    let
    List1 = {"a", "b", "c"},
    List2 = {"1", "2", "3"},
    Product = List.Transform(List2, each let currentItem = _ in List.Transform(List1, each _ & currentItem)),
    Result = List.Zip(Product),
    #"Converted to Table" = Table.FromList(Result, Splitter.SplitByNothing(), null, null, ExtraValues.Error),
    #"Extracted Values" = Table.TransformColumns(#"Converted to Table", {"Column1", each Text.Combine(List.Transform(_, Text.From), "#(tab)"), type text}),
    #"Split Column by Delimiter" = Table.SplitColumn(#"Extracted Values", "Column1", Splitter.SplitTextByDelimiter("#(tab)", QuoteStyle.Csv), {"Column1.1", "Column1.2", "Column1.3"}),
    #"Changed Type" = Table.TransformColumnTypes(#"Split Column by Delimiter",{{"Column1.1", type text}, {"Column1.2", type text}, {"Column1.3", type text}})
in
    #"Changed Type"

     

    Just put all of this M function into Advanced Editor, and the final output is as below:


    Best Regards,
    Dino Tao
    If this post helps, then please consider Accept both of our answers as the solution to help the other members find it more quickly.