Averaging part of an array powershell - arrays

Hi I am trying to return the average for part of an array, when the array is set out like
$multi = New-Object 'object[,]' $nucount,($readings + 2 )
and contains "1,4,2,6,3,4,5,nameofitem, cost of item"
I want to get an average for the first 7 elements which I know will always be the first 7 and always be a number. In the case above the number of elements containing a number will be held in a variable called $readings. So the sum I want to do is add up the elements in the array up to the $readings value. and then device by $readings.
I know of ways like this for the whole array
$Avg = ($array | Measure-Object -Average);
$Avg.Average;
or simple looping through and calculating the average buy adding and deviding.
But is there any short hand way to do this. I was going to used the ... operator
$multi[2,0..$readings] but i get an error of
Cannot convert the "System.Object[]" value of type "System.Object[]" to type "System.Int32".
Any help with this would be great if it can provide a short code to replace the
for (x=1 ; $x -eq $readings ; $X++)
{
$sum = $sum + $multi[2,$x]
{
$avg= $sum/$readings

You are going right way:
$readings=7
$array=1,4,2,6,3,4,5,"nameofitem", "cost of item"
$Avg = ($array[0..($readings - 1)] | Measure-Object -Average);
$Avg.Average;
Note that arrays are zero based…

maybe it works like this:
0..$readings | % { $sum += $multi[$_] }
or if not:
0..[int]$readings | % { $sum += $multi[$_] }
and first you have to initate $sum
$sum = 0
0..$readings | % { $sum += $multi[$_] }
$avg = $sum/$readings
here is another eample of what will work:
$arr = 1..50
$readings = 15
$arr[2..$readings]
regards Eldo.Ob

As you have indicated in your comment that array is 1-dimentional indeed, solution is straightforward:
$multi | select -First 7 | Measure-Object -Average

Try this:
$avg = (0..7 |% { $multi[2,$_] } | Measure-Object -Average)

Related

Query PSCustomObject Array for row with largest value

I'm trying to find the row with an attribute that is larger than the other row's attributes. Example:
$Array
Name Value
---- ----
test1 105
test2 101
test3 512 <--- Selects this row as it is the largest value
Here is my attempt to '1 line' this but It doesn't work.
$Array | % { If($_.value -gt $Array[0..($Array.Count)].value){write-host "$_.name is the largest row"}}
Currently it outputs nothing.
Desired Output:
"test1 is the largest row"
I'm having trouble visualizing how to do this efficiently with out some serious spaghetti code.
You could take advantage of Sort-Object to rank them by the property "Value" like this
$array = #(
[PSCustomObject]#{Name='test1';Value=105}
[PSCustomObject]#{Name='test2';Value=101}
[PSCustomObject]#{Name='test3';Value=512}
)
$array | Sort-Object -Property value -Descending | Select-Object -First 1
Output
Name Value
---- -----
test3 512
To incorporate your write host you can just run the one you select through a foreach.
$array | Sort-Object -Property value -Descending |
Select-Object -First 1 | Foreach-Object {Write-host $_.name,"has the highest value"}
test3 has the highest value
Or capture to a variable
$Largest = $array | Sort-Object -Property value -Descending | Select-Object -First 1
Write-host $Largest.name,"has the highest value"
test3 has the highest value
PowerShell has many built in features to make tasks like this easier.
If this is really an array of PSCustomObjects you can do something like:
$Array =
#(
[PSCustomObject]#{ Name = 'test1'; Value = 105 }
[PSCustomObject]#{ Name = 'test2'; Value = 101 }
[PSCustomObject]#{ Name = 'test3'; Value = 512 }
)
$Largest = ($Array | Sort-Object Value)[-1].Name
Write-host $Largest,"has the highest value"
This will sort your array according to the Value property. Then reference the last element using the [-1] syntax, then return the name property of that object.
Or if you're a purist you can assign the variable like:
$Largest = $Array | Sort-Object Value | Select-Object -Last 1 -ExpandProperty Name
If you want the whole object just remove .Name & -ExpandProperty Name respectively.
Update:
As noted PowerShell has some great tools to help with common tasks like sorting & selecting data. However, that doesn't mean there's never a need for looping constructs. So, I wanted to make a couple of points about the OP's own answer.
First, if you do need to reference array elements by index use a traditional For loop, which might look something like:
For( $i = 0; $i -lt $Array.Count; ++$i )
{
If( $array[$i].Value -gt $LargestValue )
{
$LargestName = $array[$i].Name
$LargestValue = $array[$i].Value
}
}
$i is commonly used as an iteration variable, and within the script block is used as the array index.
Second, even the traditional loop is unnecessary in this case. You can stick with the ForEach loop and track the largest value as and when it's encountered. That might look something like:
ForEach( $Row in $array )
{
If( $Row.Value -gt $LargestValue )
{
$LargestName = $Row.Name
$LargestValue = $Row.Value
}
}
Strictly speaking you don't need to assign the variables beforehand, though it may be a good practice to precede either of these with:
$LargestName = ""
$LargestValue = 0
In these examples you'd have to follow with a slightly modified Write-Host command
Write-host $LargestName,"has the highest value"
Note: Borrowed some of the test code from Doug Maurer's Fine Answer. Considering our answers were similar, this was just to make my examples more clear to the question and easier to test.
Figured it out, hopefully this isn't awful:
$Count = 1
$CurrentLargest = 0
Foreach($Row in $Array) {
# Compare This iteration vs the next to find the largest
If($Row.value -gt $Array.Value[$Count]){$CurrentLargest = $Row}
Else {$CurrentLargest = $Array[$Count]}
# Replace the existing largest value with the new one if it is larger than it.
If($CurrentLargest.Value -gt $Largest.Value){ $Largest = $CurrentLargest }
$Count += 1
}
Write-host $Largest.name,"has the highest value"
Edit: its awful, look at the other answers for a better way.

Powershell how to count all elements in a multidimensional array

I've been trying to figure out how to count all elements in an multidimensional array. But .Count only returns the first dimension.
after i gave up to find a proper solution i just created this loop to move all elements to the first dimension and count them. but this is really only a hack.
$mdarr = #((0,1,2,3,4),(5,6,7,8,9),(10,11,12,13,14))
$filecount = New-Object System.Collections.ArrayList
for($i = 0; $i -lt $mdarr.Length; ++$i) {
$filecount += $mdarr[$i]
}
$filecount.Count
How would this be done properly without processing the array first?
In the loop you are adding the elements of $mdarr[$i]. You later count the elements of the merge result. Instead of the adding to an ArrayList you could keep a count:
$xs = #((0,1,2,3,4),(5,6,7,8,9),(10,11,12,13,14))
$sum = 0;
foreach ($x in $xs) { $sum += $x.Count }
$sum // 15
# alternatively
$xs | % { $sum += $_.Count }
# or
($xs | % { $_.Count } | Measure-Object -Sum).Sum
# or
$xs | % { $_.Count } | Measure-Object -Sum | select -Expand Sum
one line code: you can flatten the multidimensional array into a anonymous array, and count the anonymous array
$xs = #((0,1,2,3,4),(5,6,7,8,9),(10,11,12,13,14))
#($xs | ForEach-Object {$_}).count #result 15
or multiline that is more readable:
$xs = #((0,1,2,3,4),(5,6,7,8,9),(10,11,12,13,14))
$xs_flatten = #($xs | ForEach-Object {$_})
$xs_flatten_count = $xs_flatten.count
echo $xs_flatten_count #result 15
put a dimension identifier index in front of .count
e.g $xs[0].count
this way, instead of returning the count of dimensions, it returns the number of rows for a given dimension

PowerShell foreach() multidimensional array based on first element

I have a fairly basic multidimensional array which looks something like this:
2017,123
2017,25
2018,5
2018,60
2017,11
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?
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 { $_[1] } | Measure-Object -Sum).Sum))
}
Assuming your array looks like "$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"

How to store outlook email body in array - Powershell?

the script below reads my outlook emails but how do I access the output. I'm new too Powershell and I'm still getting used to certain things. I just want to get the body of 10 unread outlook emails and store them in an Array called $Body.
$olFolderInbox = 6
$outlook = new-object -com outlook.application;
$ns = $outlook.GetNameSpace("MAPI");
$inbox = $ns.GetDefaultFolder($olFolderInbox)
#checks 10 newest messages
$inbox.items | select -first 10 | foreach {
if($_.unread -eq $True) {
$mBody = $_.body
#Splits the line before any previous replies are loaded
$mBodySplit = $mBody -split "From:"
#Assigns only the first message in the chain
$mBodyLeft = $mbodySplit[0]
#build a string using the –f operator
$q = "From: " + $_.SenderName + ("`n") + " Message: " + $mBodyLeft
#create the COM object and invoke the Speak() method
(New-Object -ComObject SAPI.SPVoice).Speak($q) | Out-Null
}
}
This may not be a factor here, since you're looping through only ten elements, but using += to add elements to an array is very slow.
Another approach would be to output each element within the loop, and assign the results of the loop to $body. Here's a simplified example, assuming that you want $_.body:
$body = $inbox.items | select -first 10 | foreach {
if($_.unread -eq $True) {
$_.body
}
}
This works because anything that is output during the loop will be assigned to $body. And it can be much faster than using +=. You can verify this for yourself. Compare the two methods of creating an array with 10,000 elements:
Measure-Command {
$arr = #()
1..10000 | % {
$arr += $_
}
}
On my system, this takes just over 14 seconds.
Measure-Command {
$arr = 1..10000 | % {
$_
}
}
On my system, this takes 0.97 seconds, which makes it over 14 times faster. Again, probably not a factor if you are just looping through 10 items, but something to keep in mind if you ever need to create larger arrays.
define $body = #(); before your loop
Then just use += to add the elements
Here's another way:
$body = $inbox.Items.Restrict('[Unread]=true') | Select-Object -First 10 -ExpandProperty Body

Empty value powershell array

I have a strange issue, this is my CSV:
Serveur;Carte;Cordon;IP;Mac;Vmnic ;Vmnic mac;Connect;Port
Dexter;eth1;405;172.16.5.117;00:24:e8:36:36:df;Vmnic0;00:50:56:56:36:df;sw-front-1;A1
Dexter;eth2;14;192.168.140.17;00:24:e8:36:36:e1;Vmnic1;00:50:56:56:36:e1; sw_eq_ds_1;3
;;;;;;;;
Gordon;eth1;404;172.16.5.124;b8:ac:6f:8d:ac:b4;Vmnic0;00:50:56:5d:ac:b4;;
Gordon;eth2;35;192.168.140.114;b8:ac:6f:8d:ac:b6;Vmnic1;00:50:56:5d:ac:b6;;
Gordon;eth3;254;192.168.33.10;b8:ac:6f:8d:ac:b8;Vmnic2;00:50:56:5d:ac:b8;;
So I imported it into an array with the following code:
$Serveur = #()
Import-Csv C:\Users\aasif\Desktop\myfile.csv -Delimiter ";" |`
ForEach-Object {
$Serveur += $_.Serveur
}
And to remove duplicate values I did this :
$Serveur = $Serveur | sort -uniq
So when I display my Array, I obtain these two values : Dexter and Gordon and a third null value
But I also get an empty value
The following code return 3
$Serveur.count
Why?
Thanks for your help
If you want exclude empty values you can do like this
$Serveur = $Serveur | ? { $_ } | sort -uniq
In case someone (like me) needs to remove empty elements from array, but without sorting:
$Serveur = $Serveur | Where-Object { $_ } | Select -Unique
You have an array with 3 elements, so the count is 3. The element you got from the line ;;;;;;;; isn't $null, but an empty string (""), so it counts as a valid element. If you want to omit empty elements from the array, filter them out as C.B. suggested.
On a more general note, I'd recommend against using the += operator. Each operation copies the entire array to a new array, which is bound to perform poorly. It's also completely unnecessary here. Simply echo the value of the field and assign the output as a whole back to a variable:
$csv = 'C:\Users\aasif\Desktop\myfile.csv'
$Serveur = Import-Csv $csv -Delim ';' | % { $_.Serveur } | ? { $_ } | sort -uniq

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