PowerShell - Syntax

Display output in the console:

Write-Host "Hello World"

Variable substitution:

$myvar = " World"
# Displays 'Hello World'
Write-Host "Hello$myvar"

<#
This is how I would
make a block comment
of several lines
#>

Write-Host "Goodbye$myvar"

---

If/Then/Else:

# This has some problems when the user enters an age less than 10.

# For the sake of learning, enter an age of 10 or higher when prompted.

# Your browser may not show it, but there is a space between $age and -lt

$age = Read-Host "How old are you?"

if ($age -lt 13)

{

    Write-Host "Child"

}

elseif ($age -lt 18)

{

    Write-Host "Teen"

}

else 

{

    Write-Host "Adult"

}

---

Switch (case):

# This has some problems when the user enters an age less than 10.

# For the sake of learning, enter an age of 10 or higher when prompted.

$age = Read-Host "How old are you?"

switch ($age)

{

    {$_ -lt 13 }

    {

        Write-Host "Child"

    }

    {($_ -lt 18) -and ($_ -gt 12) }

    {

        Write-Host "Teen"

    }

    default

    {

        Write-Host "Adult"

    }

}

---

Arrays:

# Empty array:
$myArray = @()

# Populated array:
$myArray = "baby", "toddler", "child", "teen", "adult"
$collectionOfAges = 0, 4, 13, 18

#Another way to define arrays:
$myArray = @("baby", "toddler", "child", "teen", "adult")

# Interact with arrays:
# child:
$myArray[2]

#
# This will not work because $myArray is a fixed array
# $myArray.Add("senior")
# 
# So instead we need a dynamic-sized array.
# Here is how to define one:

$myArray = New-Object System.Collections.ArrayList
$myArray.Add("baby")
$myArray.Add("toddler")
$myArray.Add("child")
$myArray.Add("teen")
$myArray.Add("adult")
$myArray.Add("senior")

# senior:
$myArray[5]

Write-Host "non-adults:"
$myArray[0..2]

---

Hashes:

$myHash = @{
"ford" = "mustang"
"pontiac"  = "solstice"
"chevrolet" = "camaro"
}

# Displays 'mustang'
$myHash["ford"]

# Also displays 'mustang'
$myHash.ford


# Displays 3
$myHash.Count