SharePoint Online: Update List Items from a CSV File using PowerShell

#Load SharePoint CSOM Assemblies
Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.dll"
Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.Runtime.dll"

#Parameters
$SiteURL = "https://crescent.sharepoint.com/sites/PMO"
$ListName= "Projects"
$CSVFile = "C:\Temp\ListData.csv"

#Setup Credentials to connect
$Cred = Get-Credential
 
Try {
    #Get the data from CSV file
    $CSVData = Import-CSV $CSVFile

    #Setup the context
    $Ctx = New-Object Microsoft.SharePoint.Client.ClientContext($SiteURL)
    $Ctx.Credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($Cred.UserName,$Cred.Password)
 
    #Get the List
    $List = $Ctx.Web.Lists.GetByTitle($ListName)
    $Ctx.Load($List)
    $Ctx.ExecuteQuery()

    #Loop through each Row in the CSV file and update the matching list item based on "ID"
    ForEach($Row in $CSVData)
    {
        Try {
            #Get list item to update
            $ListItem = $List.GetItemById($Row.ID)
            $Ctx.Load($ListItem)
            $Ctx.ExecuteQuery()

            #Update List Item
            $ListItem["ProjectName"] = $Row.'Project Name'
            $ListItem["IsActive"] = $Row.'Is Active'
            $ListItem["Start_x0020_Date"] = $Row.'Start Date'
            $ListItem["Status"] = $Row.'Status'
            $ListItem.Update()
            Write-host "Updated List Item:"$Row.ID
        }
        Catch {
            write-host "Error Updating Item $($Row.ID): $($_.Exception.InnerException.Message)" -foregroundcolor Yellow
        }
    }
}
Catch {
    write-host "Error: $($_.Exception.Message)" -foregroundcolor Red
}

#Config Variables
$SiteURL = "https://crescent.sharepoint.com/sites/projects"
$ListName = "Projects"
$CSVFilePath = "C:\Temp\ListData.csv"
 
#Function to get Lookup ID from Lookup Value
Function Get-LookupID($ListName, $LookupFieldName, $LookupValue)
{
    #Get Parent Lookup List and Field from Child Lookup Field's Schema XML
    $LookupField =  Get-PnPField -List $ListName -Identity $LookupFieldName
    [Xml]$Schema = $LookupField.SchemaXml
    $ParentListID = $Schema.Field.Attributes["List"].'#text'
    $ParentField  = $Schema.field.Attributes["ShowField"].'#text'
    $ParentLookupItem  = Get-PnPListItem -List $ParentListID -Fields $ParentField | Where {$_[$ParentField] -eq $LookupValue} | Select -First 1
  
    If($ParentLookupItem -ne $Null)
    {
        #Get the Parent Item ID
        Return $ParentLookupItem["ID"]
    }
    Else
    {
        Return $Null
    }
}
 
Try {
    #Connect to the Site
    Connect-PnPOnline -URL $SiteURL -Interactive
 
    #Get the data from CSV file
    $CSVData = Import-CSV $CSVFilePath
 
    #Get the List
    $List = Get-PnPList -Identity $ListName
     
    #Get fields to Update from the List - Skip Read only, hidden fields, content type and attachments
    $ListFields = Get-PnPField -List $ListName | Where { (-Not ($_.ReadOnlyField)) -and (-Not ($_.Hidden)) -and ($_.InternalName -ne  "ContentType") -and ($_.InternalName -ne  "Attachments") }
      
    #Loop through each Row in the CSV file and update the matching list item ID
    ForEach($Row in $CSVData)
    {
        #Get the List Item to update
        $ListItem = Get-PnPListItem -List $List -Id $Row.ID -ErrorAction SilentlyContinue
        If($ListItem -ne $Null)
        {
            $ItemValue = @{}            
            $CSVFields = $Row | Get-Member -MemberType NoteProperty | Select -ExpandProperty Name
            #Map each field from CSV to target list
            Foreach($CSVField in $CSVFields)
            {
                $MappedField = $ListFields | Where {$_.InternalName -eq $CSVField}
                If($MappedField -ne $Null)
                {
                    $FieldName = $MappedField.InternalName
                    #Check if the Field value is not Null
                    If($Row.$CSVField -ne $Null)
                    {
                        #Handle Special Fields
                        $FieldType  = $MappedField.TypeAsString 
                        If($FieldType -eq "User" -or $FieldType -eq "UserMulti") #People Picker Field
                        {
                            $PeoplePickerValues = $Row.$FieldName.Split(",")
                            $ItemValue.add($FieldName,$PeoplePickerValues)
                        }
                        ElseIf($FieldType -eq "Lookup" -or $FieldType -eq "LookupMulti") #Lookup Field
                        {
                            $LookupIDs = $Row.$FieldName.Split(",") | ForEach-Object { Get-LookupID -ListName $ListName -LookupFieldName $FieldName -LookupValue $_ }                
                            $ItemValue.Add($FieldName,$LookupIDs)
                        }
                        ElseIf($FieldType -eq "URL") #Hyperlink
                        {
	                        $URL = $Row.$FieldName.Split(",")[0]
	                        $Description = $Row.$FieldName.Split(",")[1]
                            $ItemValue.Add($FieldName,"$URL, $Description")
                        }
                        ElseIf($FieldType -eq "TaxonomyFieldType" -or $FieldType -eq "TaxonomyFieldTypeMulti") #MMS
                        {
                            $Terms = $Row.$FieldName.Split(",")
                            $ItemValue.Add($FieldName,$Terms)
                        }
                        Else
                        {
                            #Get Source Field Value and add to Hashtable
                            $ItemValue.Add($FieldName,$Row.$FieldName)
                        }
                    }
                }
            }
            Write-host "Updating List item ID $($Row.ID) with value:"
            $ItemValue | Format-Table
            #Update List Item value
            Set-PnPListItem -List $ListName -Identity $Row.ID -Values $ItemValue | Out-Null
        }
        Else
        {
            Write-host "Could not find item ID $($Row.ID) in the list, Skipped!" -f Yellow
        }
    }
}
Catch {
    write-host "Error: $($_.Exception.Message)" -foregroundcolor Red
}