Type Conflicts and Dynamic Casting in Powershell

The concern is documenting a mistake in the following code that aimed at adding a leading zero to the first nine months of the year (1 → 01)

$today = Get-Date
    $yyyy = $today.Year.toString()
    $MM = $today.Month.toString()
    $MM = ($MM -lt 10) ? "0$MM" : $MM

1. dynamic casting

• You can specify the type of a variable before it to force its type.
• It’s called (dynamic) casting and cast notation

2. these are 13 PowerShell types

• From Define PowerShell Data Types

3. fix

$oneDay = New-TimeSpan -Days 1
    $today = Get-Date
    [string]$yyyy = $today.Year.toString()
    $MM = $today.Month
    $MM = ($MM -lt 10) ? "0" + [string]$MM : [string]$MM

• and note that 🠋 is not working
• the cast operator limits $MM to the integer type and is not recast via the ternary operator to string even if forced

$oneDay = New-TimeSpan -Days 1
    $today = Get-Date
    [string]$yyyy = $today.Year.toString()
    [int]$MM = $today.Month
    $MM = ($MM -lt 10) ? "0" + [string]$MM : [string]$MM

• The Types of variables section of the official documentation is full of examples
• the true condition will not re-cast $MM within the ternary operator into a string

4. sources

• Define PowerShell Data Types — ss64
• Types of variables — official docs