If A or B equals C

PowerShell Help
1

Hi All,

I was writing a function today where I need the outcome to be true if A or B equal C, where see is the results of a Get-ItemProperty

Originally I had:

If $a -eq Get-ItemProperty…

Of course in order to avoid running the Get-ItemProperty cmdlet twice (due to needing to comapre it against $b as well) I have assigned the results to variable $C for use in the if statement.

Normally I would write this If A equals C or If B Equals C but was wondering, is there is a way to structure this as If A or B equal C?

Not really a big deal I was just curious if it were possible.

Thanks

2

Yep, more or less. :slight_smile:

$a = 1
$b = 3

$value = 1
if ($value -in $a, $b) {
    "it's either $a or $b, not sure which"
}
3

Thanks Joel, appreciate you taking the time to reply, I will make a note of the example as it may come in handy in the future.

Thanks again.

4

You could use the fact that -eq works differently with arrays, and returns the item if it’s in the list.

$a,$b,$c=1,2,2

$a,$b -eq $c
2

if ($a,$b -eq $c) { 'yes' }
yes

$a,$b,$c=1,2,3

$a,$b -eq $c
# null

if ($a,$b -eq $c) { 'yes' }

There is a kind of “or” regex too.

$c -match "$a|$b"
5

Yep, definitely possible. I’d probably not want to do the first one there if the array is fairly large, it’d make PS do a lot of extra work (building a whole new array, etc.) that isn’t needed in this instance.

Good call on -match, but important to remember it only works if your values are strings, or can be accurately represented when converted to strings.

6

Hmm, somehow with foreach there’s no extra memory being used (the WS doesn’t go up). And I used to correct people on this.

foreach ($i in 1..10000000) { $i;sleep 1}


# another window
ps powershell

Handles  NPM(K)    PM(K)      WS(K)     CPU(s)     Id  SI ProcessName
-------  ------    -----      -----     ------     --  -- -----------
    554      29    78136      88100       1.27   2848  59 powershell
    577      29    62704      73232       3.63  11460  59 powershell
7

Yeah, foreach just accesses each item in the array in turn, so it won’t use much, if any, extra memory. However, creating a new array does create some overhead in terms of extra memory (the amount will of course still vary based on the sizes of the arrays involved and what they contain).