Background

Employing Import-CSV to read in a datafile.

My use case will work better if I am able to comment out certain entries’ as opposed to outright removing them from the datafile.

Datafiles

Datafile – Number of Lines – 11

fullname
#Joe Smith
Aaron Hall
Ted Riley
Bob Marley
#Grant Hill
Peter Tosh
Mariah Carey
#Tinah Marie
Paul George
Michael MacDonald
Patti Labelle

Script

Outline

1. Read File
   • $listofPersons = @(Import-CSV -Path $filename -Delimiter “|”);
2. Filter List
   • Construct Discard Tag
     • Discard Tag is #`* ( Anything that starts with # )
       • Set-Variable FORMAT_ENTRY_COMMENT_SYNTAX -option Constant -value “#`*”;
   • Filter
     • Save into $listofPersonsPruned entries with property fullname that do not match our discard tag
     • $listofPersonsPruned = @($listofPersons | Where-Object {($_.fullname -notlike $FORMAT_ENTRY_COMMENT_SYNTAX)});

 

Code

<#
   Script Command Line Parameters
#> 
param ( `
		  [Parameter(Mandatory)] [string] $filename
      )
Set-StrictMode -Version Latest

$script:ErrorActionPreference = "Stop"

<#
	Declare variables
#>
[string] $log = "";

[int]    $iPersonCount = 0;
[int]    $iPersonCountPruned =0;

[string] $objectType = "";

<#
	Declare $listofPersons as an array of string
#>
$listofPersons= @();

$listofPersonsPruned= @();



<#

	Read file using
	
		 @(Import-CSV -Path $filename -Delimiter "|");
#>

$listofPersons = @(Import-CSV -Path $filename -Delimiter "|");

<#
	Get Object's Type ( $listofPersons2 )
#>
$objectType = $listofPersons.GetType();


<#
	Display Object's Type ( $listofPersons1 )
#>
Write-Host "";

$log = "Object Type (`$listofPersons):- {0}" -f $objectType;

Write-Host $log;

$iPersonCount = $listofPersons.length;

Write-Host "";

$log = "Number of Persons:- {0}" -f $iPersonCount;

Write-Host $log;


<#
	Filter out commented entries
	Entries prefixed with #
#>
Set-Variable FORMAT_ENTRY_COMMENT_SYNTAX -option Constant -value "#`*";

$listofPersonsPruned = @($listofPersons | Where-Object {($_.fullname -notlike $FORMAT_ENTRY_COMMENT_SYNTAX)});

$iPersonCountPruned = $listofPersonsPruned.length;

Write-Host "";

$log = "Number of Persons (post pruned):- {0}" -f $iPersonCountPruned;

Write-Host $log;

Use Scenario

File – Number of Lines – 11

Invoke

>powershell ./readFile.person.discard.comments.ps1 datafile_11.txt

Output

Output – Image

Output – Text

>powershell ./readFile.person.discard.comments.ps1 datafile_11.txt

Object Type ($listofPersons):- System.Object[]

Number of Persons:- 11

Number of Persons (post pruned):- 8

>

Source Code Control

GitLab

Referenced Work

1. Microsoft
   • Microsoft.PowerShell.Utility
     • Import-Csv
       Link