如何在不重复值的情况下同时展开一行列表中的所有列表? [英] How can I expand all lists in a row of lists at the same time without repeating values?

问题描述

响应

我想得到这个结果:

我不希望在处理每个后续列时在先前处理的列中重复值.

是否对 Carl 的代码进行了简单的修改，可以让我到达那里?

解决方案

也许不是很简单，但很有效:下面的代码将列与调整后的代码组合在一起，以便压缩列表并将内部列表转换为记录.接下来，列表列被展开，产生一个包含嵌套记录的列，这些记录随后被展开.

不幸的是，您不能将列与嵌套列表结合使用，因此我首先创建了一些虚拟文本列，然后将它们组合起来以生成基本代码，随后我对其进行了调整，并删除了包含虚拟列的步骤.

letSource = #table({"A", "B"}, {{ {1,2}, {3,4}} }),#"合并列" = Table.CombineColumns(Source,{"A", "B"}, each List.Transform(List.Zip(_), each Record.FromList(_,{"A","B"}))),"合并"),#"扩展合并" = Table.ExpandListColumn(#"合并列", "合并"),#"Expanded Merged1" = Table.ExpandRecordColumn(#"Expanded Merged", "Merged", {"A", "B"}, {"A", "B"})在#"扩展合并1"

In response to this question regarding how to expand all lists in a row of lists at the same time, @Carl Walsh kindly provided this succinct and helpful code:

let
Source = #table({"A", "B"}, {{ {1,2}, {3,4}} }),
Expanded = List.Accumulate(
    Table.ColumnNames(Source), 
    Source, 
    (state, column) => Table.ExpandListColumn(state, column))
in
Expanded

Which yields this:

I would like to get this result instead:

I don't want values repeated in previously processed columns as each follow-on column is processed.

Is there a simple modification to Carl's code that will get me there?

解决方案

Maybe not really simple, but effective: the code below combines the columns with adjusted code so the lists are zipped and the inner lists are transformed into records. Next the list column is expanded, resulting in a column with nested records which are subsequently expanded.

Unfortunately, you can't use combine columns with nested lists, so I created some dummy text columns first that I combined in order to generate the base code, which I subsequently adjusted and I removed the steps with the dummy columns.

let
    Source = #table({"A", "B"}, {{ {1,2}, {3,4}} }),
    #"Merged Columns" = Table.CombineColumns(Source,{"A", "B"}, each List.Transform(List.Zip(_), each Record.FromList(_,{"A","B"})),"Merged"),
    #"Expanded Merged" = Table.ExpandListColumn(#"Merged Columns", "Merged"),
    #"Expanded Merged1" = Table.ExpandRecordColumn(#"Expanded Merged", "Merged", {"A", "B"}, {"A", "B"})
in
    #"Expanded Merged1"

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