convert varying timestamps to a uniform format-CodePudding

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

CodePudding user response：

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.}