Power Query-按可变字段长度拆分列-考虑空值

Question

另一个Power Query问答提供了一种解决方案，可以根据列字符计数宽度将字符分隔的文本文件拆分为列。

但它没有考虑到null。当遇到null值时，它会在右边的一列中显示错误。我不太清楚到底发生了什么。错误为

An error occurred in the ‘SplitText’ query. Expression.Error: The 'count' argument is out of range.

拆分功能的代码为：

let
    SplitText = (text, lengths) => 
    let
        LengthsCount = List.Count(lengths),
        // Keep track of the index in the lengths list and the position in the text to take the next characters from. Use this information to get the next segment and put it into a list.
        Split = List.Generate(() => {0, 0}, each _{0} < LengthsCount, each {_{0} + 1, _{1} + lengths{_{0}}}, each Text.Range(text, _{1}, lengths{_{0}}))
    in
        Split,
    // Convert the list to a record to 
    ListToRecord = (text, lengths) => 
    let
        List = SplitText(text, lengths),
        Record = Record.FromList(List, List.Transform({1 .. List.Count(List)}, each Number.ToText(_)))
    in
        Record
in
    ListToRecord

然后，在您的表中，添加一个使用以下公式的自定义列：

each SplitText([Column1], {4, 2, 5, 3})

我使用的是Excel 2010 64位和Power Query版本：2.29.4217.1861

如何修改此项以考虑null？

Answer 1

Split = List.Generate(() => {0, 0}, each _{0} < LengthsCount, each {_{0} + 1, _{1} + lengths{_{0}}}, each try Text.Range(text, _{1}, lengths{_{0}}) otherwise null)