A better way to extract Subheading numbers using power query - excel

Question

I am attempting to extract section heading numbers from a column in excel using power query.
I have already achieved this by matching with an existing list. However, I wonder if there is a better way to achieve this in fewer steps.
M Code:
let
Source = Excel.CurrentWorkbook(){[Name="Table7"]}[Content],
#"Trimmed Text1" = Table.TransformColumns(Source,{{"Column1", PowerTrim, type text}}),
SectionNumbers = Table.AddColumn(#"Trimmed Text1", "SectionNumber", (x) => Text.Combine(Table.SelectRows(SectionNumbers, each Text.Contains(x[Column1],[SectionNumbers], Comparer.OrdinalIgnoreCase))[SectionNumbers],", ")),
#"Split Column by Delimiter2" = Table.SplitColumn(SectionNumbers, "SectionNumber", Splitter.SplitTextByEachDelimiter({","}, QuoteStyle.None, true), {"SectionNumber.1", "SectionNumber.2"}),
#"Added Custom1" = Table.AddColumn(#"Split Column by Delimiter2", "Custom", each if [SectionNumber.2] = null then [SectionNumber.1] else [SectionNumber.2]),
#"Removed Other Columns" = Table.SelectColumns(#"Added Custom1",{"Column1", "Custom"})
in
#"Removed Other Columns"
The Section numbers being matched to can be generated using:
SectionNumbers
let
Source = {1..16},
#"Converted to Table" = Table.FromList(Source, Splitter.SplitByNothing(), null, null, ExtraValues.Error),
#"Added Custom" = Table.AddColumn(#"Converted to Table", "Custom", each {1..9}),
#"Expanded Custom" = Table.ExpandListColumn(#"Added Custom", "Custom"),
#"Added Custom1" = Table.AddColumn(#"Expanded Custom", "Custom.1", each "."),
#"Merged Columns" = Table.CombineColumns(Table.TransformColumnTypes(#"Added Custom1", {{"Custom", type text}}, "en-GB"),{"Custom", "Custom.1"},Combiner.CombineTextByDelimiter("", QuoteStyle.None),"Merged"),
#"Merged Columns1" = Table.CombineColumns(Table.TransformColumnTypes(#"Merged Columns", {{"Column1", type text}}, "en-GB"),{"Column1", "Merged"},Combiner.CombineTextByDelimiter(".", QuoteStyle.None),"SectionNumbers")
in
#"Merged Columns1"
Essentially I would like a way of extracting any decimal at the start of a cell, either 15.0. or 15.0, or even 15.0.1 etc.
I have considered using regex i.e. \d+\.\d+[.] which should work however I have many rows and find that regex sometimes is computationally intensive in this case, so it takes much longer to load than the Above M Code.

Answer 1

Another power query method
Since you know your section numbers you could:
Generate a (buffered) list of all the section numbers
see if the first space-separated part of the string in column 1 exists in the Section Number list.
let
Source = Excel.CurrentWorkbook(){[Name="Table3"]}[Content],
#"Changed Type" = Table.TransformColumnTypes(Source,{{"Column1", type text}}),
//create list of all serial numbers
SerialNumbers = List.Buffer(
let
Part1 = List.Transform({1..16}, each Text.From(_) & "."),
Part2 =List.Transform({1..10}, each Text.From(_) & "."),
sn = List.Accumulate(Part1,{}, (state, current)=> state &
List.Generate(
()=>[s=current & Part2{0}, idx=0],
each [idx] < List.Count(Part2),
each [s=current & Part2{[idx]+1}, idx=[idx]+1],
each [s]))
in
sn),
#"Added Custom" = Table.AddColumn(#"Changed Type", "Custom", each
let
x = Text.Split([Column1]," "){0}
in
if List.Contains(SerialNumbers,x) then x else null, type text)
in
#"Added Custom"

Answer 2

How about
let Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
#"Added Custom" = Table.AddColumn(Source, "Custom", each if Text.PositionOfAny([Column1], {"0".."9"})>=0 then Text.BeforeDelimiter(Text.From([Column1])," ") else null)
in #"Added Custom"