CODEWITHSUNDEEP
powershell
7_R3X
7_R3X

Reputation: 4370

Running Cmdlet with equality comparision operator

Running the following command in Powershell 7.0.3 returns true

[datetime]'2020-08-09' -eq 'August 9, 2020'

But, I want to replace the right side of the command with Get-Date. I wonder how I can do it. If I'm not wrong (Please correct me if I am), we can do it in bash using the by enclosing the command in ticks(`).

I've tried the Invoke-Command cmdlet but I get the same error:

> [datetime]'2020-08-09' -eq Invoke-Command Get-Date
ParserError:
Line |
   1 |  [datetime]'2020-08-09' -eq Invoke-Command Get-Date
     |                            ~
     | You must provide a value expression following the '-eq' operator.

Can someone help me out with it or point me in the right direction?

Upvotes: 0

Views: 107

Answers (1)

Theo
Theo

Reputation: 61068

To compare a datetime object with another, you need to make sure that other part is also a datetime object. This is why you need to put brackets around the right-hand side of the equasion, so the command in there is evaluated first.

As Lee_Dailey mentioned, the result of [datetime]'2020-08-09' is a date object with the time part set to 0:00:00 (midnight).

As example of how it will work is:

[datetime]'2020-08-09' -eq (Get-Date).Date

Another thing to consider is the fact that constructing the date using [datetime]'2020-08-09' will leave you with a datetime object that has its .Kind property set to Unspecified.
If you are comparing this to the resulting datetime object that stores a UTC date (= has its .Kind property set to 'Utc)', the equasion will still go wrong (unless your current timezone IS actually UTC)

We can fake this by doing

[datetime]'2020-08-09' -eq (Get-Date).Date.ToUniversalTime()

Which in my timezone would return False.

P.S. It is wrong to compare a datetime object to a formatted date string.
It may have worked in your case, because apparently the .ToString() method of a datetime object happens to format in 'yyyy-MM-dd' on your system. On different locales however comparing like this will fail .

Upvotes: 1

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