Expression.Error：我们无法将值 3 转换为函数类型

Posted 2023-04-14

【中文标题】Expression.Error：我们无法将值 3 转换为函数类型

【英文标题】：Expression.Error: We cannot convert the value 3 to type Function

【发布时间】：2021-03-11 19:26:52

【问题描述】：

在此代码中需要一些帮助。不知怎的，我弄错了语法：

    let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("jdE7CsMwFETRrRjVBuk9fV1KK0hvXCYQCAhi758YnCoEdMuBU91ZV+OdFbHqzGxu/X08+uvZp1rrueu+349JzDYDpox5xgJjkbHEWGasMLZcTKwoyDtiyphnLDAWGUuMZcYKY1deidadL8gg75ApY56xwFhkLDGWGSuMffOmP6y19sN0QS8MmTLmGQuMRcYSY5mxwtiZd/sA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Date = _t, Portofolio = _t, Asset = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,"Date", type date),
    #"Sorted Rows" = Table.Sort(#"Changed Type","Asset", Order.Ascending,"Date", Order.Ascending),
    #"Grouped Rows" = Table.Group(#"Sorted Rows", "Asset", "t_Asset", each _, type table [Date=nullable text, Portofolio=nullable text, Asset=nullable text]),
    #"Added Custom" = Table.AddColumn(#"Grouped Rows", "Row-1", each Table.SelectRows([t_Asset], Table.RowCount([t_Asset])-1))
in
    #"Added Custom"

error image

这是我期望实现的目标。

Example

我刚刚想通了！感谢那些试图提供帮助的人！

let
Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("jdE7CsMwFETRrRjVBuk9fV1KK0hvXCYQCAhi758YnCoEdMuBU91ZV+OdFbHqzGxu/X08+uvZp1rrueu+349JzDYDpox5xgJjkbHEWGasMLZcTKwoyDtiyphnLDAWGUuMZcYKY1deidadL8gg75ApY56xwFhkLDGWGSuMffOmP6y19sN0QS8MmTLmGQuMRcYSY5mxwtiZd/sA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Date = _t, Portofolio = _t, Asset = _t]),
        #"Changed Type" = Table.TransformColumnTypes(Source,"Date", type date),
        #"Sorted Rows" = Table.Sort(#"Changed Type","Asset", Order.Ascending,"Date", Order.Ascending),
        #"Grouped Rows" = Table.Group(#"Sorted Rows", "Asset", "t_Asset", each _, type table [Date=nullable text, Portofolio=nullable text, Asset=nullable text]),
        #"Added Custom" = Table.AddColumn(#"Grouped Rows", "t_Index", each Table.AddIndexColumn([t_Asset], "Index", 1, 1, Int64.Type)),
        #"Removed Columns" = Table.RemoveColumns(#"Added Custom","t_Asset"),
        #"Added Custom1" = Table.AddColumn(#"Removed Columns", "Portfolio", each Table.SelectRows([t_Index],(Innertable)=> Innertable[Index] = Table.RowCount([t_Index])-1)),
        #"Removed Columns1" = Table.RemoveColumns(#"Added Custom1","t_Index"),
        #"Expanded Portfolio" = Table.ExpandTableColumn(#"Removed Columns1", "Portfolio", "Portofolio", "Portofolio")
in
    #"Expanded Portfolio"

【参考方案1】：

您是否尝试从上一行获取 t_asset 表？

let Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("jdE7CsMwFETRrRjVBuk9fV1KK0hvXCYQCAhi758YnCoEdMuBU91ZV+OdFbHqzGxu/X08+uvZp1rrueu+349JzDYDpox5xgJjkbHEWGasMLZcTKwoyDtiyphnLDAWGUuMZcYKY1deidadL8gg75ApY56xwFhkLDGWGSuMffOmP6y19sN0QS8MmTLmGQuMRcYSY5mxwtiZd/sA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Date = _t, Portofolio = _t, Asset = _t]),
#"Changed Type" = Table.TransformColumnTypes(Source,"Date", type date),
#"Sorted Rows" = Table.Sort(#"Changed Type","Asset", Order.Ascending,"Date", Order.Ascending),
#"Grouped Rows" = Table.Group(#"Sorted Rows", "Asset", "t_Asset", each _, type table [Date=nullable text, Portofolio=nullable text, Asset=nullable text]),
#"Added Index" = Table.AddIndexColumn(#"Grouped Rows", "Index", 0, 1),
#"Added Custom" = Table.AddColumn(#"Added Index", "Row-1", each try #"Added Index"[Index]-1[t_Asset] otherwise null)
in #"Added Custom"

【讨论】：

嗨，我正在尝试从每个表中获取最后的负 1 条记录。

您从三列开始——日期、投资组合、资产。您对资产进行分组。您想在第 2 行显示第 1 行的哪些字段？以上已经完成了整个表格请发布所需的示例输出

【参考方案2】：

如果需要获取表格的倒数第二行（作为表格），最后一步应该是这样的：

= Table.AddColumn(#"Grouped Rows", "Row-1", each Table.LastN(Table.RemoveLastN([t_Asset]),1))

如果您的目标是获得一个表格，其中包含每个资产的倒数第二行，那么您可以使用以下代码：

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("jdE7CsMwFETRrRjVBuk9fV1KK0hvXCYQCAhi758YnCoEdMuBU91ZV+OdFbHqzGxu/X08+uvZp1rrueu+349JzDYDpox5xgJjkbHEWGasMLZcTKwoyDtiyphnLDAWGUuMZcYKY1deidadL8gg75ApY56xwFhkLDGWGSuMffOmP6y19sN0QS8MmTLmGQuMRcYSY5mxwtiZd/sA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Date = _t, Portofolio = _t, Asset = _t]),
    types = Table.TransformColumnTypes(Source,"Date", type date),
    group = Table.Group(types, "Asset", "temp", each let a = Table.Sort(_,"Date",0)
                                                        in aTable.RowCount(_)-2),
    expand = Table.ExpandRecordColumn(group, "temp", "Date", "Portofolio")
in
    expand

【讨论】：

谢谢。请看我的原帖。刚刚想通了。