Calculate the time difference between two timestamps

Question

I want to calculate the difference between two time stamp no matter even it is second, here below is my code snippet:

#Start Timer
$Start_Timer = (Get-Date).DateTime
Write-Host "Start Timer is ---> $Start_Timer"
#End Timer
$End_Timer = (Get-Date).DateTime
Write-Host "End Timer is ---> $End_Timer"
$Current_Time_End = (Get-Date).DateTime
$TotalExecutionTime = $End_Timer - $Start_Timer

Output of the above code is:

Start Timer is ---> Monday, August 13, 2018 6:21:18 PM
End Timer is ---> Monday, August 13, 2018 6:22:55 PM

Error generated

Cannot convert value "Monday, August 13, 2018 6:22:55 PM" to type
"System.Int32". Error: "Input string was not in a correct format."
At D:\Eclipse_Repository\self_repo\jmallick\FileMover.ps1:55 char:1
+ $TotalExecutionTime = $End_Timer - $Start_Timer
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidArgument: (:) [], RuntimeException
    + FullyQualifiedErrorId : InvalidCastFromStringToInteger

What I am doing wrong here?

Answer 1

(Get-Date).DateTime is a string so you cannot do mathematical operations. You can verify this with (Get-Date).DateTime.gettype().fullname.

Using subtraction on the pure date objects e.g. $beforeTime = Get-Date will be what you want to do. This will also return TimeSpan objects

(get-date) - ((get-date).addhours(-1))

Also read this relevant post about calculating execution time in .Net and using StopWatch in PowerShell

Answer 2

I use this

$t1 = (get-date)
$t2 = (get-date)
$tdiff = $t2-$t1

Output variable example:

$tdiff
$tdiff.minutes
$tdiff.hours

etc

Answer 3

I recommend using [StopWatch] for performance measurement. See following example:

$timer = [System.Diagnostics.Stopwatch]::StartNew()
#do your job
$timer.Stop()

#get timespan
$timer.Elapsed

Answer 4

Use this: New-TimeSpan -Start $Start_Timer -End $TotalExecutionTime You'll have time difference expressed in multiple increments (days, seconds etc).