Allow Get-Random -Count to return duplicates

Summary of the new feature/enhancement

Get-Random should be able to return the same result multiple times when the Count parameter is specified.
Today when you run: 1..10 | Get-Random -Count 10
you will always get one of each number from 1-10 but you should be able to get any number multiple times.
This would also fix an issue where you get fewer items than you expected because there weren’t enough inputobjects:
1..10 | Get-Random -Count 20

Proposed technical implementation details (optional)

A switch parameter like -Unique or -AllowDuplicates could be added to control this behavior VS the current one.
I like the “Unique” parameter name, but having a switch that is enabled by default (for backwards compatibility) is a bad user experience IMO.

[jhoneill]

@MartinGC94
I think this working as designed at present.

If you want numbers between 1 and 10 with possible repetitions, then

get-random -Minimum 1 -Maximum 10 -Count 10` 

does the trick. But if you want the first n of a randomly ordered set this returns it .

get-verb | get-random -count 10

And works for any object.

Note that this Get-Random -InputObject @('Heads','Tails') -Count 10 Stops after two. There is no error if count > set_size.

@237dmitry 's example with 2* actually needs to be count * so (e.g) the verb “Set” can appear 10 times.

But if you want the option to select items in the set more than once these are better

$v = get-verb
get-random -Minimum 0 -Maximum $v.Count -Count 20 | ForEach-Object {$v[$_]} 

or

 1..10 | % {Get-Random -InputObject @('Heads','Tails') }

A switch -allowduplicates which only applies when -inputObject is specified would clean this up.

[jazzdelightsme]

It’s true; I learned the term in a college class (don’t remember if it was a straight-up CS course or a required-for-CS stats course).

The etymology of the term is simple, though: suppose you are drawing some colored marbles out of a sack, one at a time. From this you can pose the question “what is the chance you will draw N of the same color in a row” or somesuch. Naturally this depends on the numbers of different-colored marbles in the sack, but it also depends on your drawing behavior: after drawing a marble, do you put it back into the sack before drawing the next one? (i.e. do you replace it?)

Hence “selection WITH replacement” (putting the marbles back as you draw them), or “selection WITHOUT replacement” (don’t put any marbles back in).

If I saw an -AllowDuplicates parameter here, I might also be confused. I could wonder if it meant that if there are duplicates in the input, then without this param I will get an error? (because otherwise they are not “allowed”)

So I feel like the better tradeoff would be to use the more precise technical term. Yes, people might have to read the doc if they haven’t had a stats course; but better to raise the general educational level of everyone than keep the confusing term for everyone (honestly, everyone would probably have to read the doc to understand what -AllowDuplicates would actually mean for this cmdlet, too).