convert varying timestamps to a uniform format

Question

I am trying to convert a timestamp to milliseconds in a script using an external program. The external program outputs the time in the shortest possible format Example the external program can output any of the following formats:

"1:33.823" #1min:33 seconds.823 - shortest
"11:33.823" #11min:33 seconds.823 - short
"1:11:33.823" #1 hour 11min:33 seconds.823 - long

I need this value converted in milliseconds. so I tried [timestamp] $mystring but it complains about the format in the first case. I thought about parsing the format manually with something like

$format='h\:mm\:ss\.ff'
[timespan]::ParseExact($mystring,$format , $null)

But the problem with this approach is that I have to predict every possible output format of the external program and implement all the cases manually (if shortest then $format=m\:ss\.fff else if short then $format=...

Or I can possibly split and define the string, loop from the back and define the attributes of the TimeSpan object manually.

My question is: are there any standard (good practice) conversion methods for my case provided in the language or are my "quick and dirty" solutions common?

Thanks

It sounds like the "external program" is reporting elapsed time and not a timestamp. I think you want to use `[timespan]::Parse($mystring) `. — Jonathan Dodds, Jan 08 '23 at 20:49
@JonathanDodds, yes it is elapsed time actually, `$t="1:33.823";[timespan]::Parse($t)` won't work, thus the question — user206904, Jan 08 '23 at 20:52
TimeSpan can accept an array : $formats = @("m:s.fff", "h:m:s.fff") Then use [timespan]::ParseExact($mystring,$formats , $null) but doesn't work. You need to use DateTime instead : [DateTime]::ParseExact($mystring,$formats , $null).TimeOfDay I debugged in c#. Have seen case in the past like this where timespan doesn't work but DateTime does. You always can use timeofday to convert DateTime to TimeSpan. — jdweng, Jan 08 '23 at 21:44

mklement0 · Accepted Answer · 2023-01-08T23:13:32.513

If you ensure that your time-span strings have at least 3 :-separated components, you can cast them directly to [timespan] (which, behind the scenes, delegates to [timespan]::Parse($inputString, [cultureinfo]::InvariantCulture))^[1]

@(
  "1:33.823" #1min:33 seconds.823 - shortest
  "11:33.823" #11min:33 seconds.823 - short
  "1:11:33.823" #1 hour 11min:33 seconds.823 - long
) | ForEach-Object {
  $colonCount = ($_ -replace '[^:]').Length
  [timespan] ('0:' * [math]::Max(0, (3 - $colonCount - 1)) + $_)
}

The above transforms the input strings to 0:1:33.823, 0:11:33.823, and 1:11:33.823 before casting, i.e. prepends 0: components as needed.

^{[1] PowerShell by design uses the invariant culture when possible - see this answer for more information.}

this is indeed quite elegant, the idea I had for padding was to match and divide to 4 case with 4x if statements, if the string is case 1 (seconds only): pad with 2x 0 zeroes, if case 2 (minutes only), pad with -X zeroes, etc — user206904, Jan 09 '23 at 00:18

convert varying timestamps to a uniform format

1 Answers1