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XavJSY New Member
New Member

Create a dynamic combo list based on 3 other lists

Hi

 

I need to create a dynamic list feeding from 3 different lists:

Say I have the 3 following lists X,Y and Z currently containing the following values:

 

X: a b c

Y: A B C

Z: 1 2 3

 

and I need to create the dynamic list "Combo X,Y,Z" showing all possible combination of values in X,Y and Z:

 

a A 1

a A 2

...

c C 3

 

and I need "Combo X,Y,Z" to update automatically whenever I modify X, Y or Z.

 

The list I have are all Excel tables, would anyone know if that's possible to do in Excel and if not in PBI and how I could train myself to code that?

 

Thanks in advance

1 ACCEPTED SOLUTION

Accepted Solutions
jclark88 Frequent Visitor
Frequent Visitor

Re: Create a dynamic combo list based on 3 other lists

In SQL i'd normally use a cross join to create the cartesian product of all values - basically, joining every row with every other row. I'm not sure this is possible in power query, but you can trick it by creating a custom column for all input tables that has the same value, then doing some joins on these columns (all the values are the same so every row will join with every other row)..

 

I've knocked together the power query here (might be a more effecient way but this seems to work):

 

 

let

    //Our source tables, replace with whatever, just make sure the Colum header is "Val"
    X = Table.FromList({"a","b","c"}, null, {"Val"}),
    Y = Table.FromList({"A","B","C"}, null, {"Val"}),
    Z = Table.FromList({"1","2","3"}, null, {"Val"}),
    

    //Adding custom column for join
    X_2 = Table.AddColumn(X, "JoinCol", each 1),
    Y_2 = Table.AddColumn(Y, "JoinCol", each 1),
    Z_2 = Table.AddColumn(Z, "JoinCol", each 1),

    //Join all the tables together
    Join_1 = Table.NestedJoin(X_2,"JoinCol",Y_2,"JoinCol","Y"),
    Join_2 = Table.NestedJoin(Join_1,"JoinCol",Z_2,"JoinCol","Z"),

    //Remove the custom column
    RemoveCol = Table.RemoveColumns(Join_2,{"JoinCol"}),
    
    //Expand out our Y and Z columns
    ExpandY = Table.ExpandTableColumn(RemoveCol, "Y", {"Val"}, {"Y.Val"}),
    ExpandZ = Table.ExpandTableColumn(ExpandY, "Z", {"Val"}, {"Z.Val"}),

    //Rename the columns to something we expect
    RenameColumns = Table.RenameColumns(ExpandZ,{{"Val", "X"}, {"Y.Val", "Y"}, {"Z.Val", "Z"}})

in
    RenameColumns

This outputs a table like this: 

 

X,Y,Z

aA1
aA2
aA3
aB1
aB2
aB3
aC1
aC2
aC3
bA1
bA2
bA3
bB1
bB2
bB3
bC1
bC2
bC3
cA1
cA2
cA3
cB1
cB2
cB3
cC1
cC2
cC3
1 REPLY 1
jclark88 Frequent Visitor
Frequent Visitor

Re: Create a dynamic combo list based on 3 other lists

In SQL i'd normally use a cross join to create the cartesian product of all values - basically, joining every row with every other row. I'm not sure this is possible in power query, but you can trick it by creating a custom column for all input tables that has the same value, then doing some joins on these columns (all the values are the same so every row will join with every other row)..

 

I've knocked together the power query here (might be a more effecient way but this seems to work):

 

 

let

    //Our source tables, replace with whatever, just make sure the Colum header is "Val"
    X = Table.FromList({"a","b","c"}, null, {"Val"}),
    Y = Table.FromList({"A","B","C"}, null, {"Val"}),
    Z = Table.FromList({"1","2","3"}, null, {"Val"}),
    

    //Adding custom column for join
    X_2 = Table.AddColumn(X, "JoinCol", each 1),
    Y_2 = Table.AddColumn(Y, "JoinCol", each 1),
    Z_2 = Table.AddColumn(Z, "JoinCol", each 1),

    //Join all the tables together
    Join_1 = Table.NestedJoin(X_2,"JoinCol",Y_2,"JoinCol","Y"),
    Join_2 = Table.NestedJoin(Join_1,"JoinCol",Z_2,"JoinCol","Z"),

    //Remove the custom column
    RemoveCol = Table.RemoveColumns(Join_2,{"JoinCol"}),
    
    //Expand out our Y and Z columns
    ExpandY = Table.ExpandTableColumn(RemoveCol, "Y", {"Val"}, {"Y.Val"}),
    ExpandZ = Table.ExpandTableColumn(ExpandY, "Z", {"Val"}, {"Z.Val"}),

    //Rename the columns to something we expect
    RenameColumns = Table.RenameColumns(ExpandZ,{{"Val", "X"}, {"Y.Val", "Y"}, {"Z.Val", "Z"}})

in
    RenameColumns

This outputs a table like this: 

 

X,Y,Z

aA1
aA2
aA3
aB1
aB2
aB3
aC1
aC2
aC3
bA1
bA2
bA3
bB1
bB2
bB3
bC1
bC2
bC3
cA1
cA2
cA3
cB1
cB2
cB3
cC1
cC2
cC3