Converting strings to datetime objects that have variable digits for days

Question

I have the following in an array variable

Mon May  1 08:13:18 2017
Sat Apr 29 19:07:14 2017

In order to update the format and timezone, I have to run these two ParseExact commands first.

$time | ForEach-Object {$_ = [datetime]::ParseExact($_,'ddd MMM  d HH:mm:ss yyyy',[System.Globalization.CultureInfo]::InvariantCulture)} 

$time | ForEach-Object {$_ = [datetime]::ParseExact($_,'ddd MMM dd HH:mm:ss yyyy',[System.Globalization.CultureInfo]::InvariantCulture)}

I get an error on the one that fails (which is expected)

Exception calling "ParseExact" with "3" argument(s): "String was not recognized as a valid DateTime."
At D:\UPDATING.ps1:
+ ... ach-Object {$_ = [datetime]::ParseExact($_ ...
+                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
+ FullyQualifiedErrorId : FormatException

Everything works in the long run and I can do my formatting, but I would like to know if there is a better of doing this rather than using 2 parseExacts

$time | % { [DateTime]::ParseExact($_, [string[]]('ddd MMM d HH:mm:ss yyyy', 'ddd MMM dd HH:mm:ss yyyy'), [CultureInfo]::InvariantCulture, 'None') } or $time | % { [DateTime]::ParseExact($_, 'ddd MMM d HH:mm:ss yyyy', [CultureInfo]::InvariantCulture, 'AllowInnerWhite') } — user4003407
– user4003407, Commented May 1, 2017 at 12:36
@PetSerAl Oooooo. That is so much better I forgot it could take multiple arguments. — Matt
– Matt, Commented May 1, 2017 at 14:45
all the answers provided worked. I am going to using this $time | % { [DateTime]::ParseExact($_, 'ddd MMM d HH:mm:ss yyyy', [CultureInfo]::InvariantCulture, 'AllowInnerWhite') } @PetSerAl If you put it in to an answer I'll mark it. — mattnicola
– mattnicola, Commented May 2, 2017 at 3:56

user4003407 · Accepted Answer · 2017-05-02 09:55:09Z

3

There are multiple overloads of ParseExact method. One of them allows you to specify multiple patterns of date to parse:

$time = 'Sat Apr 29 19:07:14 2017', 'Mon May  1 08:13:18 2017'
$time | % { [DateTime]::ParseExact($_, [String[]]('ddd MMM  d HH:mm:ss yyyy',
                                                  'ddd MMM dd HH:mm:ss yyyy'), [CultureInfo]::InvariantCulture, 'None') }

Also there are overloads, which allow you to specify additional parse options, like [Globalization.DateTimeStyles]::AllowInnerWhite, to allow additional whitespace characters inside parsed string:

$time | % { [DateTime]::ParseExact($_, 'ddd MMM d HH:mm:ss yyyy', [CultureInfo]::InvariantCulture, 'AllowInnerWhite') }

answered May 2, 2017 at 9:55

user4003407

22.3k4 gold badges54 silver badges62 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Mark Wragg · Accepted Answer · 2017-05-01 11:27:49Z

2

There is an extra space in your first date and a single digit day, so the pattern would actually need to be ddd MMM d HH:mm:ss yyyy.

Full command:

[datetime]::ParseExact($_,'ddd MMM  d HH:mm:ss yyyy',[System.Globalization.CultureInfo]::InvariantCulture)

However, this isn't the case for your second date. A single d will still work for this but the changing in space is an issue you might need to program around. One solution would be to replace all double spaces with singles first.

This seems to work for both dates, here's a proof of concept:

$dates = "Sat Apr 29 19:07:14 2017","Mon May  1 08:13:18 2017"
$dates = $dates -replace '  ',' '

$dates | ForEach-Object {
    [datetime]::ParseExact($_,'ddd MMM d HH:mm:ss yyyy',[System.Globalization.CultureInfo]::InvariantCulture)
}

edited May 1, 2017 at 11:27

answered May 1, 2017 at 11:15

Mark Wragg

23.6k7 gold badges48 silver badges77 bronze badges

6 Comments

Matt Over a year ago

I don't think the extra space is the root of the problem. You can see it is accounted for in the question with the first of the two parse statements. I think the actual issue is with the variable integer days which can be one digit or two depending. Looks like the OP runs both commands against the strings knowing one will succeed and expects the other to fail.

mattnicola Over a year ago

@Matt yes, that is correct. Mark's response is a way around the issue by deleting the "extra" space in the day

Matt Over a year ago

@mattnicola What is it suppose to be? It says Mon in the question?

Mark Wragg Over a year ago

It's now a date time object so you need to use -format to reformat the output if you want to.

mattnicola Over a year ago

Maybe a different Q, (and its not really an issue for me), but why is the output now in this format Saturday, April 29, 2017 7:07:14 PM

|

Collectives™ on Stack Overflow

Converting strings to datetime objects that have variable digits for days

2 Answers 2

Comments

6 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

6 Comments

Your Answer

Sign up or log in

Post as a guest

Related