Testing Numbers and Date

With a bit of creativity (and the help from the -as operator), you can create powerful test functions. These two test for valid numbers and valid DateTime information:

PS> function Test-Numeric($Value) { ($Value -as [Int64]) -ne $null }
PS> function Test-Date($Value) { ($Value -as [DateTime]) -ne $null }

If things get more complex, you can combine tests. This one tests for valid IP addresses:

function Test-IPAddress($Value) {
 ($Value -as [System.Net.IPAddress]) -ne $null -and ($Value -as [Int]) -eq $null 
}

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