希望这有帮助!
我假设了一个位置，因为我不喜欢声明没有文本路径的文件路径。请根据需要调整路径。

$Files = Get-ChildItem J:\Test\*.txt -Recurse 

$Filecount = 0

$ObjectCollectionArray = @()

#Fist parse and collect each row in an array.. While keeping the datetime information from filename. 

foreach($File in $Files){

$Filecount++
Write-Host $Filecount 

$DateTime = $File.fullname.split(" ").split(".")[1]

$Content = Get-Content $File.FullName

foreach($Row in $Content){

    $Split = $Row.Split("`t")

    if($Split[0] -ne 'Wavelength'){

        $Object = [PSCustomObject]@{
            'Datetime' = $DateTime
            'Number' = $Split[0]
            'Wavelength' = $Split[1]
        }

        $ObjectCollectionArray += $Object
    }
}    
}

#Match by number and create a new object with relation to the number and different datetime. 

$GroupedCollection = @()
$Grouped =  $ObjectCollectionArray | Group-Object number

foreach($GroupedNumber in $Grouped){
    $NumberObject = [PSCustomObject]@{
            'Number' = $GroupedNumber.Name
    }

foreach($Occurance in $GroupedNumber.Group){
        $NumberObject | Add-Member -NotePropertyName $Occurance.Datetime -NotePropertyValue $Occurance.wavelength
}

$GroupedCollection += $NumberObject

}

$GroupedCollection | Export-Csv -Path J:\Test\result.csv -NoClobber -NoTypeInformation

你要做的是一个相当困难的任务，有几种方法可以做到。这种方法要求所有的文件都在内存中来处理它们。你完全可以把这些文件当作TSVs，所以Import-Csv -Delimiter "t"`是一个选项，这样你就可以处理对象而不是纯文本。

# using this temp dictionary to create objects for each line of each tsv
$tmp  = [ordered]@{}
# get all files and enumerate
$csvs = Get-ChildItem $location -Filter *.asd.txt | ForEach-Object {
    # get their content as objects
    $content  = $_ | Import-Csv -Delimiter "`t"
    # get their property Name that is not `Wavelength`
    $property = $content[0].PSObject.Properties.Where{ $_.Name -ne 'Wavelength' }.Name

    # output an object holding the total lines of this csv,
    # its content and the property name of interest
    [pscustomobject]@{
        Lines    = $content.Count
        Content  = $content
        Property = $property
    }
}

# use a scriptblock to allow streaming so `Export-Csv` starts exporting as
# output is going through the pipeline
& {
    # for loop used for each line of the Tsv having the highest number of lines
    for($i = 0; $i -lt [System.Linq.Enumerable]::Max([int[]] $csvs.Lines); $i++) {
        # this boolean is used to preserve the "Wavelength" value of the first Tsv
        $isFirstCsv = $true

        foreach($csv in $csvs) {
            # if this is the first object
            if($isFirstCsv) {
                # add the value of "Wavelength"
                $tmp['Wavelength'] = $csv.Content[$i].Wavelength
                # and set the bool to false, since we are only using this once
                $isFirstCsv = $false
            }
            # then add the value of each property of each Tsv to the temp dictionary
            $tmp[$csv.Property] = $csv.Content[$i].($csv.Property)
        }

        # then output this object
        [pscustomobject] $tmp
        # clear the temp dictionary
        $tmp.Clear()
    }
} | Export-Csv path\to\result.csv -NoTypeInformation

这里有一个更有效的方法，将文件作为纯文本处理，这个方法更快，内存效率更高，但不可靠。它使用StreamReader来读取文件内容 * 逐行 *，并使用StringBuilder来构造每一行。

& {
    # get all files and enumerate
    $readers = Get-ChildItem $location -Filter *.asd.txt | ForEach-Object {
        # create a stream reader for each file
        [System.IO.StreamReader] $_.FullName
    }

    # this StringBuilder is used to construct each line
    $sb = [System.Text.StringBuilder]::new()
    # while any of the readers has more content
    while($readers.EndOfStream -contains $false) {
        # signals this is our first Tsv
        $isFirstReader = $true
        # enumerate each reader
        foreach($reader in $readers) {
            # if this is the first Tsv
            if($isFirstReader) {
                # append the line as-is, only trimming exces white space
                $sb = $sb.Append($reader.ReadLine().Trim())
                $isFirstReader = $false
                # go to next reader
                continue
            }
            # if this is not the first Tsv,
            # split on Tab and exclude the first token (Wavelength)
            $null, $line = $reader.ReadLine().Trim() -split '\t'
            # append a Tab + this line
            $sb = $sb.Append("`t$line")
        }
        # append a new line and output the constructed string
        $sb.AppendLine().ToString()
        # and clear it for next lines
        $sb = $sb.Clear()
    }

    # dispose all readers when done
    $readers | ForEach-Object Dispose
} | Set-Content path\to\result.tsv -NoNewline