PowerShell foreach() multidimensional array based on first element

Question

I have a fairly basic multidimensional array which looks something like this:

I wish to run a ForEach() loop or similar function to total the numbers in the second element based on the year indicated in the first so that I end up with an output like this:

2017,159
2018,65

How do I best accomplish this?

Please show us the code with which you define the array and assign the values. Answer may differ based on whether it's an actual multidimensional array, a jagged/nested array or a flat array of objects — Mathias R. Jessen
– Mathias R. Jessen, Commented Feb 28, 2018 at 21:33
It is a pretty basic array. It is populated within a loop and looks something like this: $myArray += ,($year, $amount) — Bjørn H. Sandvik
– Bjørn H. Sandvik, Commented Feb 28, 2018 at 21:39
I've been trying, but my PS skills clearly aren't there yet :( — Bjørn H. Sandvik
– Bjørn H. Sandvik, Commented Feb 28, 2018 at 22:05

mklement0 · Accepted Answer · 2018-02-28 22:31:54Z

2

The following solution is concise, but not fast:

# input array
$arr = 
  (2017,123),
  (2017,25),
  (2018,5),
  (2018,60),
  (2017,11)

# Group the sub-arrays by their 1st element and sum all 2nd elements
# in each resulting group.
$arr | Group-Object -Property { $_[0] } | ForEach-Object {
  , ($_.Name, (($_.Group | ForEach-Object { $_[1] } | Measure-Object -Sum).Sum))
}

answered Feb 28, 2018 at 22:31

mklement0

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1 Comment

mklement0 Over a year ago

@BjørnH.Sandvik: My pleasure; glad it was helpful.

qbanet359 · Accepted Answer · 2018-02-28 21:41:26Z

0

Assuming your array looks like "$array" this will give you what you need:

$2017total = 0
$2018total = 0

$array = "2017,123",
"2017,25",
"2018,5",
"2018,60",
"2017,11" | % { 

if ($_ -match '2017') {
    $2017 = ($_ -split ',')[1]
    $2017total += $2017
}
else {
    $2018 = ($_ -split ',')[1]
    $2018total += $2018
} 
}

Write-Host "2017,$2017total"
Write-Host "2018,$2018total"

answered Feb 28, 2018 at 21:41

qbanet359

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2 Comments

Bjørn H. Sandvik Over a year ago

I very much appreciate the approach, but the array may contain any number of different years in the first element. I am looking for a way to handle this variety dynamically..

Bjørn H. Sandvik Over a year ago

In SQL-speak, what I am looking for is akin to SELECT SUM(COLUMN2) GROUP BY COLUMN1 ORDER BY COLUMN1

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