02-array

https://learn.microsoft.com/en-us/powershell/scripting/learn/deep-dives/everything-about-arrays?view=powershell-7.6

Array

Array are fixed size
Array stores the references, not the values, so when modifying items in a nested array, it will change everything
Basic syntax

$mylist=@()
$mylist = 1,2,3,4,5
$mylist = echo 1 2 3 4 5

Get/Set

$mylist[$i]
$mylist[$i..$j] # Slicing
$mylist[$i,$j,$i] # Slicing with custom
$mylist[$i] = $i

• if index out of range, no error will occur, it will be $null
• PowerShell Slicing IS inclusive

Count

$mylist.Count # or Length

Add item into an array

$mylist+="fruits"
$mylist+=@(1,2) # will be ...,1,2 not ...,[1,2]

• when using this method to add a list, it will unpack the list

Remove an item from an array

$mylist=$mylist -ne 1

• -ne get all the items in that array that does not equal to that value, hence removing that item

Creating an array from string

"1,2,3".split(";")

Operators

Join the array into a string

$mylist -join "-" # the delimiter can be empty

Checking membership

$var -in $mylist
$mylist -contains $var
$mylist -ccontains $var

• the ccontain makes the match case sensitive

Filter

$mylist | where {$_ -eq condition }

ArrayList

It’s a dynamic size

$mylist = New-Object -TypeName System.Collections.ArrayList

Add

$mylist.Add(1) # return the index
$mylist.AddRange(@()) # add a range from an array, similar to extend

• add will always echo into the termina, use void to

[void]$mylist.Add(1)

Remove

$mylist.Remove(value)
$mylist.RemoveAt(index)
$mylist.RemoveRange(index, deleteCount)

• remove is not the same as pop
• it remove one instance where it matches the value from the beginning
• RemoveRange is similar to JavaScript splice