Category: Reference

Reference sheet for my powershell class

Arrays seem to be like small temporary databases ? 😀

 

Creating an Array:

C:\PS>$numbers = @(4,7,9,11,20)     //creates array and populates entries with data
C:\PS>write-host $numbers     //prints entire array

Number 9 can be retrieved with

C:\PS>$numbers[2]    //prints 3rd item in array (integers start at 0

similarly

C:\PS>write-host $numbers[2] “this is the second item in the array”    //includes text at the end and uses the write-host command

C:\PS>$names = @(“Martin”, “Emma”, “Alan”, “Laura”)
    //this is how words are stored into an array.

Or you can  can create an empty array and then add elements later:

C:\PS>$MoreNames = @() 
C:\PS>$MoreNames += “Emma” 
C:\PS>$MoreNames += “John” 
C:\PS>$MoreNames += “Gerald”

The size of the array can be retrieved with the commands

C:\PS>$ArrayName.count 

OR
C:\PS>$ArrayName.length

(Both these seem to return the same values)

An array can be auto populated with a number range by using double dots to tell powershell to fill in the gap. eg:

C:\PS>$range = @(10..50)

Will create an array containing the numbers 10, through to and including 50.

To retrieve the last item from the array, you can use either

C:\PS>$array[$array.Length-1]

OR

C:\PS>$array[-1]

To retrieve the FIRST item in an array, you first get the length, you substitute the [-1] with [-$array.count] . Or any variation of these to your desired item.

 To store the output from a command to an array, use cmdlets:

C:\PS>$array = Get-Process

To create an array that already has item spaces for a set amount of items, you can use:

C:\PS>$NameArray = New-Object String[] 8 
C:\PS>$IntArray = New-Object Int[] 12

Beginning Assignment:

CLS  #clears all the crap off the screen from the last thing i ran 😀

write-host “Press any key to Start”
$x = $host.UI.RawUI.ReadKey(“NoEcho,IncludeKeyDown”) #waits for a key to be pushed before continuing
write-host “”
write-host “Generating random numbers”

$Item0 = Get-Random -minimum 0 -maximum 99 #Generates a random number between 0 and 99 and stores it in $Item0
$Item1 = Get-Random -minimum 0 -maximum 99
$Item2 = Get-Random -minimum 0 -maximum 99
$Item3 = Get-Random -minimum 0 -maximum 99
$Item4 = Get-Random -minimum 0 -maximum 99
$Item5 = Get-Random -minimum 0 -maximum 99
$Item6 = Get-Random -minimum 0 -maximum 99
$Item7 = Get-Random -minimum 0 -maximum 99
$Item8 = Get-Random -minimum 0 -maximum 99
$Item9 = Get-Random -minimum 0 -maximum 99

$RandomArray = @($Item0, $Item1, $Item2, $Item3,$Item4,$Item5,$Item6,$Item7,$Item8,$Item9) #stores the randomly generated numbers into $RandomArray
write-host “”
write-host “Now all the numbers are generated and stored in the `$RandomArray` array,”
write-host “we will use a sort that puts the largest into the”
write-host “variable until its reached the end of the array.”
write-host “”
[array]::sort($RandomArray) #sorts the array ?

write-host “”
write-host “The largest number in the array is” $RandomArray[-1] #writes out the last item of $RandomArray
write-host “”

 

update: next exercise involved those freaking factorials, i am once again lost and unsure how to continue <,<

WHY DO I GET STUCK ON THESE

also, i cant get loops into my head in this stupid language, why is C/C++ easier than this ?

isn’t powershell meant to be a baby language or something?