How can I "zip" two arrays in PowerShell?

Question

I want to zip two arrays, like how Ruby does it, but in PowerShell. Here's a hypothetical operator (I know we're probably talking about some kind of goofy pipeline, but I just wanted to show an example output).

PS> @(1, 2, 3) -zip @('A', 'B', 'C')
@(@(1, 'A'), @(2, 'B'), @(3, 'C'))

Do you want to keep them as arrays (array of arrays), or just all values as one array? — Bali C
– Bali C, Commented Mar 30, 2017 at 15:23
I do NOT want to merge the arrays. I need the elements as pairs for later processing, hopefully in a pipeline. — Anthony Mastrean
– Anthony Mastrean, Commented Mar 30, 2017 at 15:26
@RogerLipscombe That looks like an answer that is better than rolling your own function — Matt
– Matt, Commented Mar 30, 2017 at 15:44
[Linq.Enumerable]::Zip((1, 2, 3), ('A', 'B', 'C'), [Func[Object, Object, Object[]]]{,$args}) — user4003407
– user4003407, Commented Mar 30, 2017 at 15:45

Anthony Mastrean · Accepted Answer · 2017-05-18 18:13:02Z

31

There's nothing built-in and it's probably not recommended to "roll your own" function. So, we'll take the LINQ Zip method and wrap it up.

[System.Linq.Enumerable]::Zip((1, 2, 3), ('A', 'B', 'C'), [Func[Object, Object, Object[]]]{ ,$args })

That works, but it's not pleasant to work with over time. We can wrap the function (and include that in our profile?).

function Select-Zip {
    [CmdletBinding()]
    Param(
        $First,
        $Second,
        $ResultSelector = { ,$args }
    )

    [System.Linq.Enumerable]::Zip($First, $Second, [Func[Object, Object, Object[]]]$ResultSelector)
}

And you can call it simply:

PS> Select-Zip -First 1, 2, 3 -Second 'A', 'B', 'C'
1
A
2
B
3
C

With a non-default result selector:

PS> Select-Zip -First 1, 2, 3 -Second 'A', 'B', 'C' -ResultSelector { param($a, $b) "$a::$b" }
1::A
2::B
3::C

I leave the pipeline version as an exercise to the astute reader :)

PS> 1, 2, 3 | Select-Zip -Second 'A', 'B', 'C'

answered May 18, 2017 at 18:13

Anthony Mastrean

22.5k24 gold badges118 silver badges190 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

mklement0 Over a year ago

Nicely done. As for a hypothetical operator: while not an operator, an enhancement was proposed to the foreach statement, along the lines of foreach ($elementFromArray1, $elementFromArray2 in @(1, 2, 3), @('A', 'B', 'C')) { ... } - unfortunately, it was declined - see GitHub issue #14732

zett42 Over a year ago

With PS 7.x we can also use the Linq.Enumerable.Zip overload that outputs tuples, alleviating the need to pass a function: [Linq.Enumerable]::Zip( [int[]](1, 2, 3), [string[]]('A', 'B', 'C')). Note that the arrays must be typed because otherwise PowerShell can't find the correct overload.

zett42 Over a year ago

If you don't know the types of the arrays beforehand, casting to [object[]] arrays also works: [Linq.Enumerable]::Zip( [object[]](1, 2, 3), [object[]]('A', 'B', 'C') )

dudeNumber4 Over a year ago

Using powershell core, if my arrays are typed coming into a function, it's simply [Linq.Enumerable]::Zip($arr1, $arr2)

Lukasz Mendakiewicz · Accepted Answer · 2020-06-14 08:53:00Z

6

# Multiple arrays
$Sizes = @("small", "large", "tiny")
$Colors = @("red", "green", "blue")
$Shapes = @("circle", "square", "oval")

# The first line "zips"
$Sizes | ForEach-Object { $i = 0 }{ @{size=$_; color=$Colors[$i]; shape=$Shapes[$i]}; $i++ } `
 | ForEach-Object { $_.size + " " + $_.color + " " + $_.shape }

Outputs:

small red circle
large green square
tiny blue oval

answered Jun 14, 2020 at 8:53

Lukasz Mendakiewicz

4724 silver badges8 bronze badges

Collectives™ on Stack Overflow

How can I "zip" two arrays in PowerShell?

2 Answers 2

4 Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

4 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related