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In this exercise, we will discuss how variable types are handled in PowerShell and a few advanced ways to interact with variables, including enforcing types, creating multiple variables, and a few variable-related cmdlets.

Variable Types

The following are some common types of variables:

Int: integers like 2, -5, 99
String: zero or more characters enclosed in double quotes like "Codecademy!", "3X4mP|3"
Boolean: two possible values: $True and $False
Array: a collection of items like 25, "red", $False, 16.30

PowerShell assigns a type to the variable depending on the value we assign to it. This is called dynamic typing. The default type of any uninitialized variable is $null.

We can append .GetType().Name to the variable reference to determine a variable’s data type.

PS > $my_string_variable = "Hello, World!"
PS > $my_string_variable.GetType().Name
String

In the example above, we are accessing the Name property of the GetType() method of a variable we initialized.

The GetType() method returns the name and base type property for a variable
Accessing the Name property only returns the data type we desire
The variable’s data type is String

Constrained Variables

If we wish to enforce a certain type on a variable, we can create a constrained variable via casting.

PS > [Int]$age = 25
PS > $age
25

PS > [Int]$age = "twenty five"
Cannot convert value "age" to type "System.Int32". Error: "Input string was not in a correct format."

When initializing a variable, we specify the type in brackets before referencing the variable. Attempting to assign a value of another type results in an error if PowerShell cannot convert it.

Create Multiple Variables

PowerShell allows us to create multiple variables using one statement. To initialize multiple variables with the same value,

$i = $j = $k = 0

To assign multiple values to multiple variables,

$number, $color, $bool = 25, "red", $false

We will next discuss a specific type of variable called an environment variable.

Instructions

At the top of the variable_types.ps1 file, create a constrained variable of type Int and the name $num_1. Assign $num_1 the value 42.

Click Run when you are done.

Create another constrained variable in the the variable_types.ps1 file of type Int and the name $num_2. Give $num_2 the value "forty two".

You will encounter an error, but it works as intended! Data of String type cannot be assigned to a variable expecting an Int.

Click Run when you are done.

Now create three variables using one comma-separated statement.

The first variable should be called $name and initialized to your name in a string format.
The second variable should be called $color and initialized to your favorite color in a string format.
The third and final variable should be called $date and assign (Get-Date).DateTime to it.

Click Run when you are done.

Initialize the $date_data_type variable to the data type of the date variable and click Run.

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