CODEWITHSUNDEEP
sortingpowershell
knb
knb

Reputation: 9295

powershell: import-csv | get-member: sort column names / property names based on (original) position. rename colnames?

The get-member commandlet returns NoteProperties always sorted alphanumerically. See sample output below.

From import-csv I received an array in memory, now I want get-member to sort the member names by original position rather than its alphanumerical value.

The original sequence is visible in the $_.psextended.Definition string ( column names joined by commas)

I cannot in-place edit the property names, as it's read-only. As I workaround I tried to prepend a numeric prefix to the column name, see code below

Any better ideas? I don't want to in-place edit the original data file.

 $content = (import-csv -delimiter "`t" $infile_abs  );
 $colnames = $content | get-Member |  where-object {$_.MemberType -eq "NoteProperty"} ; #| out-gridview; 
 $cols = $content | get-Member -force | where-object {$_.Name -eq "psextended"} ; 
 echo($cols.Definition -replace "psextended" , "");

 $i = 0;
 $colnames| sort-object  -descending |  foreach-object { 
   $i++ ; 
   $cn = [string]::Format( "{0:00}_{1}",   $i, $_.Name )  ;
   Write-Host  $cn
 };

Sample Output of psextended

{File Name, Label, ObsDateTime, Port#, Obs#, Exp_Flux, IV Cdry, IV Tcham, IV Pressure, IV H2O, IV V3, IV V4, IV RH}

Output of $colnames = $content | get-Member | out-gridview; 

Exp_Flux    NoteProperty    System.String Exp_Flux=0,99 
File Name   NoteProperty    System.String File Name=xxx-11040   
IV Cdry NoteProperty    System.String IV Cdry=406.96    
IV H2O  NoteProperty    System.String IV H2O=9.748  
IV Pressure NoteProperty    System.String IV Pressure=100.7 
IV RH   NoteProperty    System.String IV RH=53.12   
IV Tcham    NoteProperty    System.String IV Tcham=16.19    
IV V3   NoteProperty    System.String IV V3=11.395  
IV V4   NoteProperty    System.String IV V4=0.759   
Label   NoteProperty    System.String Label=5m  
Obs#    NoteProperty    System.String Obs#=1    
ObsDateTime NoteProperty    System.String ObsDateTime=2011-04-04 13:19:37   
Port#   NoteProperty    System.String Port#=1

EDIT: (No answers yet)

Here is a custom sorting function, now I need to tell Get-Member to use this sorting function. How to do this in a pipeline?

 #$orig_seq = $cols.Definition -replace "psextended", "" -replace "[{}]", "";
 $orig_seq = "File Name, Label, ObsDateTime, Port#, Obs#, Exp_Flux, IV Cdry, IV Tcham, IV Pressure, IV H2O, IV V3, IV V4, IV RH";

 echo $orig_seq;
 #exit;

  &{

   $byPos= @{};
   $i = 0; 
   $orig_seq.Split(",") | % { $byPos[$i++] = $_.trim()}
   $order = ([int[]] $byPos.keys) | sort
   #$order | %{ ([string]::Format( "{0} => {1}",  $_, $byPos[$_])) }
   $order | %{ $byPos[$_] }

 }

Upvotes: 2

Views: 11287

Answers (3)

sturmstrike
sturmstrike

Reputation: 647

I approached this in a slightly different way when processing a CSV file:

# Create a stream object where $filepath is the CSV file you're processing
$stream = [System.IO.File]::Open($filepath, [System.IO.FileMode]::Open)

# Create a reader of the stream, yes there are more efficient ways to do this
$reader = New-Object -typename System.IO.StreamReader -argumentlist $stream

# Output the first line to the target CSV file you're processing then move on...
$reader.ReadLine() | Out-File $outpath -Encoding "ASCII"

Less 'powershelly', but easy to achieve...

Upvotes: 0

knb
knb

Reputation: 9295

I found the answer in question PSCustomObject to Hashtable

The in-memory data from import-csv cmdlet is a PSCustomObject.

Its properties (column names) can be fetched in the original order with this code

 #fetch in correct order
 $content.psobject.properties |
 # do something with the column names
 Foreach { $ht2["$($_.Name)"] =  $_.Value }

Properties can be renamed this way, see

http://powershell.com/cs/blogs/tips/archive/2009/05/08/renaming-object-properties.aspx

dir | Select-Object @{Name='FileName'; Expression={$_.Name}}

Upvotes: 1

Emiliano Poggi
Emiliano Poggi

Reputation: 24826

Just a trace: 

$myorder = $orig_seq.split(",")

foreach $myobject in $myobjects {

 $myorder | % {get-member -name $_ -inputobject $myobject}

}

EDIT: get sorted values

$myorder = $orig_seq.split(",")

foreach $myobject in $myobjects {

 $mysortedvalues | ? {$myobject.name -eq $_}

}

Obviously this is useful and feasable if you now $mysortedvalues in advance.

Upvotes: 0

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