Background

Experienced a little error using Import-CSV.

Error

PropertyNotFoundException

Error Image

Error Text

The property 'length' cannot be found on this object. Verify that the property exists.

At line:1 char:1

+ ./readFile.person.original.ps1 datafile_01.txt
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [readFile.person.original.ps1], PropertyNotFoundException
    + FullyQualifiedErrorId : PropertyNotFoundStrict,readFile.person.original.ps1

 

Datafiles

Datafile – Number of Lines – 01

fullname
Joe Smith

 

Datafile – Number of Lines – 02

fullname
Joe Smith
Aaron Hall

 

Code

Original

 

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

$script:ErrorActionPreference = "Stop"

<#
	Declare variables
#>
[string] $log = "";
[int]    $iPersonID =0;
[int]    $iPersonCount = 0;

[string] $personFullName = "";


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

$bDebug = $true;

<#
    Server Count
#>
$iPersonID =0;

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

$iPersonCount = $listofPersons.length;

Write-Host "";

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

Write-Host $log;

Import-CSV -Path $filename -Delimiter "|" | ForEach {

    #Write-Host $_;
	
	<#
		set local variables
	#>
	
	$personFullName = $_.fullname
	
	Write-Host "";
	
	$log = "`t Fullname:- {0}" -f $personFullName;
	
	Write-Host $log;
	
}

Revision

 

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

$script:ErrorActionPreference = "Stop"

<#
	Declare variables
#>
[string] $log = "";
[int]    $iPersonID =0;
[int]    $iPersonCount = 0;

[string] $personFullName = "";

[string] $objectType1 = "";
[string] $objectType2 = "";

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

$listofPersons1 = @();
$listofPersons2 = @();

$bDebug = $true;

<#
    Server Count
#>
$iPersonID =0;


<#
	$listofPersons= Import-CSV -Path $filename -Delimiter "|" ;
#>

<#

	Original
	--------
		$listofPersons= Import-CSV -Path $filename -Delimiter "|" ;
		
	Revision
	--------
		$listofPersons= @( Import-CSV -Path $filename -Delimiter "|" );
		
#>

Write-Host "";

$log = "Filename:- {0}" -f $filename;

Write-Host $log;

<#
	Read file using
		 Import-CSV -Path $filename -Delimiter "|";
#>

$listofPersons1= Import-CSV -Path $filename -Delimiter "|";


<#
	Get Object's Type ( $listofPersons1 )
#>
$objectType1 = $listofPersons1.GetType();

<#

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

$listofPersons2= @(Import-CSV -Path $filename -Delimiter "|");

<#
	Get Object's Type ( $listofPersons2 )
#>
$objectType2 = $listofPersons2.GetType();


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

$log = "Object Type (`$listofPersons1):- {0}" -f $objectType1;

Write-Host $log;

<#
	Display Object's Type ( $listofPersons2 )
#>
Write-Host "";

$log = "Object Type (`$listofPersons2):- {0}" -f $objectType2;

Write-Host $log;

$iPersonCount = $listofPersons2.length;

Write-Host "";

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

Write-Host $log;


Import-CSV -Path $filename -Delimiter "|" | ForEach {

    #Write-Host $_;
	
	<#
		set local variables
	#>
	
	$personFullName = $_.fullname
	
	Write-Host "";
	
	$log = "`t Fullname:- {0}" -f $personFullName;
	
	Write-Host $log;
	
}

Use Scenario

Original Code

File – Number of Lines – 2

Invoke

powershell ./readFile.person.original.ps1 datafile_02.txt

Output

Output – Image

Output – Text

>powershell ./readFile.person.original.ps1 datafile_02.txt

Number of Persons :- 2

         Fullname:- Joe Smith

         Fullname:- Aaron Hall

>

File – Number of Lines – 1

Invoke

powershell ./readFile.person.original.ps1 datafile_01.txt

Output

Output – Image

Output – Text

>powershell ./readFile.person.original.ps1 datafile_01.txt

readfilepersonreadFile.person.original.ps1 : The property 'length' cannot be found on this object. Verify that the property exists.
At line:1 char:1
+ ./readFile.person.original.ps1 datafile_01.txt
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [readFile.person.original.ps1], PropertyNotFoundException
    + FullyQualifiedErrorId : PropertyNotFoundStrict,readFile.person.original.ps1

>

Revised Code

File – Number of Lines – 2

Invoke

powershell ./readFile.person.revised.ps1 datafile_02.txt

Output

Output – Image

Output – Text

>powershell ./readFile.person.revised.ps1 datafile_02.txt

Filename:- datafile_02.txt

Object Type ($listofPersons1):- System.Object[]

Object Type ($listofPersons2):- System.Object[]

Number of Persons:- 2

         Fullname:- Joe Smith

         Fullname:- Aaron Hall

>

File – Number of Lines – 1

Invoke

powershell ./readFile.person.revised.ps1 datafile_01.txt

Output

Output – Image

Output – Text

>powershell ./readFile.person.revised.ps1 datafile_01.txt
Filename:- datafile_01.txt

Object Type ($listofPersons1):- System.Management.Automation.PSCustomObject

Object Type ($listofPersons2):- System.Object[]

Number of Persons:- 1

Fullname:- Joe Smith

>

Troubleshooting

Import-CSV

1. Number of Records in Source File
   • Factor:- Number of records in source file
     • Returned Object
       • Number of records is 1
         • System.Management.Automation.PSCustomObject
       • Number of records is 2
         • System.Object[]
     • Implication
       • Functions that expects for the returned object to be a collection will fail
       • i.e.
         • Length

Workaround

How to force a method to return an object array.

Well try the @() Array Subexpression operator.

 

SS64.COM

@( ) Array Subexpression operator.

 

 

Source Code Control

GitLab

Referenced Work

1. Microsoft
   • Microsoft.PowerShell.Utility
     • Import-Csv
       Link
2. Anees Asghar
   • What does @() mean in PowerShell Script?
     Link
3.  SS64
   • Syntax Operators
     Link