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November 1, 2017 at 3:34 pm

I have a time value such as '23:10:00' to which I need to add, say, 10:00:01, but I am not interested in the time of day, just the total. Using

(Get-Date '23:10:00').AddHours(10)

usually produces 07:10:00, ie the next day. How to I simply arrive at the total 30:10:01 without adding each individual part?

November 1, 2017 at 3:39 pm

Take your $originalTime, and create $newTime by adding your days (or whatever) to it. Then subtract $newTime – $originalTime.

The result of the subtraction will be a System.TimeSpan, which has methods for expressing the time span as hours or days or whatever you want.

November 1, 2017 at 3:45 pm

Many thanks. I tried this and there was a Timespan returned, but it just showed the total I originally added. What I need is the sum of the two. I am sorry if I am missing something very basic here.

November 1, 2017 at 4:10 pm

(get-date).hour + 10

That will return the hour as an integer which you could then add hours to get a running total. Without knowing the purpose of the result, it's hard to suggest other solutions.

If you want to use a date/time object, it's concerned about the date and time, so I don't think you'll find a way without adding hours, minutes and seconds separately.

November 1, 2017 at 5:06 pm

How's that? It rounds it to days though. You can leave out the second [timespan].

[timespan]'23:10:00' + [timespan]'10:00:01'

November 1, 2017 at 11:22 pm

This is workable, as I can format the TotalHours,TotalMinutes,TotalSeconds returned to a usable result. As I said earlier the result I am after here is 33:10:01 in this example. I cannot use (Get-Date) as it returns an hour from the next day if the total exceeds 24 hours.
I have now cobbled together a working script which demonstrates what I am trying to achieve; and just for good measure there is also a subtract function:

[Int]$h = [Int]$m = [Int]$s = 0
function Add ([String]$test) {
   $temp = $test.Split(':')
   $SCRIPT:h+= $temp[0]
   $SCRIPT:m+= $temp[1]
   $SCRIPT:s+= $temp[2]
   if ($SCRIPT:s -gt 59) {
      [Int]$min = $SCRIPT:s/60
      [Int]$sec = $SCRIPT:s%60
      $SCRIPT:m+= $min
      $SCRIPT:s = $sec
   if ($SCRIPT:m -gt 59) {
      [Int]$hour = $SCRIPT:m/60
      [Int]$min  = $SCRIPT:m%60
      $SCRIPT:h+= $hour
      $SCRIPT:m = $min
function Subtract ([String]$test) {
   $minus = $test.Split(':')
   if (($SCRIPT:s - [Int]$minus[2]) -lt 0) {   
      $SCRIPT:s+= (60 - [Int]$minus[2])
      [Int]$minus[1]+= 1
   } else {
      $SCRIPT:s = $SCRIPT:s - [Int]$minus[2]
   if (($SCRIPT:m - [Int]$minus[1]) -lt 0) { 
      $SCRIPT:m+= (60 - [Int]$minus[1])
      [Int]$minus[0]+= 1
   } else {
      $SCRIPT:m = $SCRIPT:m - [Int]$minus[1]
   $SCRIPT:h = $SCRIPT:h - $minus[0]
Add '23:43:15'
Add '00:26:25'
Add '12:23:29'
$result = "{0:D3}:{1:D2}:{2:D2}" -f $h, $m, $s
Write-Host $result

if ($result -gt '10:45:08') { #No point trying if too large a value.
   Subtract '10:45:08'
   $result = "{0:D3}:{1:D2}:{2:D2}" -f $h, $m, $s
   Write-Host $result

If there is a simpler way I would much appreciate it if one of you experts could please enlighten me.

November 2, 2017 at 1:41 pm

This one is simpler:

$now = Get-Date '23:10:00'
$then = $now.AddHours(10).AddMinutes(0).AddSeconds(1)
$timespan = $then - $now
"{0:D3}:{1:D2}:{2:D2}" -f $hrs,$then.Minute,$then.Second

November 2, 2017 at 2:02 pm

$result = [timespan]'23:10:00' + '10:00:01'
'{0:d2}:{1:d2}:{2:d2}' -f [int]$result.totalhours, $result.minutes, $result.Seconds


[timespan]'33:10:01' is 33 days though.

November 2, 2017 at 11:42 pm

But this fails:

$result = [timespan]'24:10:00' + '10:00:01'

After adding a bunch of times I often exceed 24 hours so cannot use this one. Likewise Get-Date '24:10:00' throws an error.