Using range operator with a step

Question

The PowerShell range operator generates a list of values:

>1..6

1
2
3
4
5
6

How can I generate a list of values with a specific step? For example, I need a list from 1 to 10 with step 2.

Imtiaz

Answer 1

The range operator itself doesn't support skipping/stepping, but you could use Where-Object (or the Where() method if you're running version 4.0 or above) to filter out every second:

PS C:\> (1..10).Where({$_ % 2 -eq 0})
2
4
6
8
10

Version 2.0 and up:

PS C:\> 1..10 |Where-Object {$_ % 2 -eq 0}
2
4
6
8
10

Bili

understand, but my powershell returns error for published sample. Updated code (1..10) | where ({$_ % 2 -eq 0}) returns correct result – Imtiaz

@constructor: I guess the capability to call extension methods is new in PowerShell 5. I haven't seen or used it either so far. I also think most PowerShell code should not use LINQ but rather the respective cmdlets. – Stereoscopy

Ahh, you are running PowerShell 2.0? If so, the Where() method doesn't exist, but yes, as mentioned, the Where-Object cmdlet will work just as well – Bili

@Stereoscopy The Where() extension method was introduced in PowerShell 4.0 - it's not LINQ, it's a PS language feature. OP didn't mention which version he was running – Bili

Oh, nice to know. I kinda lost track of the newer language features. – Stereoscopy

I have assuming lowest common denominator for answers lately. I am missing out on newer features as well :( – Exegetic

@Exegetic Unless there's an obvious idiomatic way of doing something, I usually try to present alternatives. .Where() operates significantly faster on large collections (no pipeline overhead) – Bili

I wonder why no one commented on the fact this is actually a bit different than what was requested. The steps should be offset from the original position and not from 0, as is the common interpretation of steps on a range. Should probably update the condition in the answer to be ($_-<first-element>) % 2 -eq 0 or 1..10 |Where-Object {($_-1) % 2 -eq 0} in this specific case. – Stingaree