Measure-Latest: finding latest date/time

Today I needed to find the latest date/time value from a set of values and stumbled upon an issue with the standard measure-object cmdlet failing for DateTime values (click the link to vote for this to be fixed by the way).

Obviously, as a true PowerSheller, whenever I come across a limitation like that I simply use the extensibility of PowerShell to get through. Here’s the Measure-Latest function which I created. It takes the values from the pipeline and outputs the latest of them (or $null if the pipeline was empty or only had $null values):

# get a set of DateTime values from the pipeline
# filter out $nulls and produce the latest of them
# (c) Dmitry Sotnikov
function Measure-Latest {
    BEGIN { $latest = $null }
    PROCESS {
            if (($_ -ne $null) -and (($latest -eq $null) -or ($_ -gt $latest))) {
                $latest = $_ 
            }
    }
    END { $latest }
}

Usage is pretty simple:

# when was the last time something was modified in the current folder?
dir | foreach { $_.LastWriteTime } | Measure-Latest

Enjoy!

Tags: Examples, KB, Knowledge Base, Known Issues, PowerShell
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