Formatting PowerShell Get-Date inside string - powershell

Question

I can't get my head around how formatting a datetime variable inside a string works in PowerShell.
$startTime = Get-Date
Write-Host "The script was started $startTime"
# ...Do stuff...
$endTime = Get-Date
Write-Host "Done at $endTime. Time for the full run was: $( New-TimeSpan $startTime $endTime)."
gives me the US date format while I want ISO 8601.
I could use
$(Get-Date -Format u)
but I want to use $endTime to make the calculation of the timespan correct.
I have tried all permutations of $, (, ), endTime, -format, u, .ToString(...) and .ToShortDate(), but the one that works.

Answer 1

"This is my string with date in specified format $($theDate.ToString('u'))"
or
"This is my string with date in specified format $(Get-Date -format 'u')"
The sub-expression ($(...)) can include arbitrary expressions calls.
Microsoft Documents both standard and custom DateTime format strings.

Answer 2

You can use the -f operator
$a = "{0:D}" -f (get-date)
$a = "{0:dddd}" -f (get-date)
Spécificator Type Example (with [datetime]::now)
d Short date 26/09/2002
D Long date jeudi 26 septembre 2002
t Short Hour 16:49
T Long Hour 16:49:31
f Date and hour jeudi 26 septembre 2002 16:50
F Long Date and hour jeudi 26 septembre 2002 16:50:51
g Default Date 26/09/2002 16:52
G Long default Date and hour 26/09/2009 16:52:12
M Month Symbol 26 septembre
r Date string RFC1123 Sat, 26 Sep 2009 16:54:50 GMT
s Sortable string date 2009-09-26T16:55:58
u Sortable string date universal local hour 2009-09-26 16:56:49Z
U Sortable string date universal GMT hour samedi 26 septembre 2009 14:57:22 (oups)
Y Year symbol septembre 2002
Spécificator Type Example Output Example
dd Jour {0:dd} 10
ddd Name of the day {0:ddd} Jeu.
dddd Complet name of the day {0:dddd} Jeudi
f, ff, … Fractions of seconds {0:fff} 932
gg, … position {0:gg} ap. J.-C.
hh Hour two digits {0:hh} 10
HH Hour two digits (24 hours) {0:HH} 22
mm Minuts 00-59 {0:mm} 38
MM Month 01-12 {0:MM} 12
MMM Month shortcut {0:MMM} Sep.
MMMM complet name of the month {0:MMMM} Septembre
ss Seconds 00-59 {0:ss} 46
tt AM or PM {0:tt} ““
yy Years, 2 digits {0:yy} 02
yyyy Years {0:yyyy} 2002
zz Time zone, 2 digits {0:zz} +02
zzz Complete Time zone {0:zzz} +02:00
: Separator {0:hh:mm:ss} 10:43:20
/ Separator {0:dd/MM/yyyy} 10/12/2002

Answer 3

Instead of using string interpolation you could simply format the DateTime using the ToString("u") method and concatenate that with the rest of the string:
$startTime = Get-Date
Write-Host "The script was started " + $startTime.ToString("u")