Update SharePoint list field using powershell based on Date comparison - powershell

Question

I am currently try to update SharePoint field (Dropdown field called Overdue to Yes if the dateFormat field is equal or less than current date. At this stage, it does not change the value. Is there anything that i missed. Please refer the code i have below. Thanks
if((Get-PSSnapin | Where {$_.Name -eq "Microsoft.SharePoint.PowerShell"}) -eq $null) {
Add-PSSnapin Microsoft.SharePoint.PowerShell;
}
$SPWeb = Get-SPWeb "http://contoso/sites/test";
$List = $SPWeb.Lists["Catalog"];
$currentDate = Get-Date (Get-Date) -format dd/MM/yyyy;
$items = $List.Items;
foreach ($item in $items) {
$deadline = $item["TA Deadline"];
$dateFormat = Get-Date $deadline -format dd/MM/yyyy;
#if date Format is less or equal than current date then update the Overdue drop down field to yes
if($dateFormat -le $currentDate)
{
$item["Overdue"] = "YES"
$item.Update()
}
}
$SPWeb.Dispose();

Answer 1

I think you need to supply an index/numerical numerical value for the choice. See the blog post here.
As it mentions you could do:
$item["Overdue"] = 0; #assuming 0 == YES
Or
$item["Overdue"] = $list.Fields["Overdue"].GetFieldValue("YES");
New code for the datetime logic
if((Get-PSSnapin | Where {$_.Name -eq "Microsoft.SharePoint.PowerShell"}) -eq $null) {
Add-PSSnapin Microsoft.SharePoint.PowerShell;
}
$SPWeb = Get-SPWeb "http://contoso/sites/test";
$List = $SPWeb.Lists["Catalog"];
$currentDate = Get-Date;
$items = $List.Items;
foreach ($item in $items) {
$deadline = $item["TA Deadline"];
$dateFormat = [datetime]$deadline
#if date Format is less or equal than current date then update the Overdue drop down field to yes
if($dateFormat -le $currentDate)
{
$item["Overdue"] = "YES"
Write-Debug $item["Overdue"]
$item.Update()
}
}
$SPWeb.Dispose();

Answer 2

if the Overdue column is a yes/no field (Boolean) I guess You can either do like Dana V suggested, so:
$item["Overdue"] = 0
or
$item["Overdue"] = $true