Question

I am new in powershell but was wondering how do you get combination of given numbers without repetition ?

for e.g

$a = (1,2,3,4)
$n = 4
$k = 2

output :-

12
13
14
23
24
34

if K = 3 then

123
124
134
234

Answer 1

Just a quick solution for that particular case, I don’t see much value in it because I feel there are tools designed for such exercises… 😉

$a = (1,2,3,4)

$rest = New-Object Collections.ArrayList
$a[1..($a.Length - 1)] | foreach { $rest.Add($_) | Out-Null }

$prefix = $a[0]

$(while ($rest) {
    foreach ($suffix in $rest) {
        -join ($prefix, $suffix)
    }
    $prefix = $rest[0]
    $rest.RemoveAt(0)
}) -join ', '