How To Effectively Use PowerShell Variables

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Variables are objects that can store data. In PowerShell, a variable name starts with a $ character.

A variable can be given any name. It can contain a mix of letters, numbers, symbols, or spaces.
The variable names in PowerShell are case insensitive.
You can assign a value to a variable using the assignment (=) operator.
A variable is created by simply assigning a value to it.
For example, the below command creates a variable named $myName and assigns it a string value. The double quotes (” “) indicate that a string value is being assigned to the variable.

How To Use PowerShell Variables — PowerShell Variables

Variables can be categorized into :

User-defined variables – Variables declared by the user which is session-oriented.
Automatic Variables – Variables that store the state of the information in the PowerShell console.
Environment variables – Variables that hold the environment in which programs run.

How To Assign Values To PowerShell Variables

Highlights:Storing multiple objects in a variableDiscovering the variable’s type, properties and methodsVariable declarationDemosteps:

Step 1: A variable name can include spaces and special characters. In such a case, the name has to be enclosed in curly braces {}.

Assigning values to powershell variables — Assigning Values

Step 2: The properties and methods that an object can use depend on the object’s type. You can get a variable’s object type by calling its GetType method.

$myName.GetType()

Step 3: You can use the Get-Member cmdlet to see what properties and methods are available for the variable.

$variableName | Get-Member

Step 4: Variables can store multiple objects as well. For example, you can store a list of PowerShell command in a variable, by just assigning the output of Get-Command to the variable.

$command = Get-Command

Step 5: When you include a variable’s name inside a double-quoted string, PowerShell replaces the variable’s name with its value in the string.

"Hello, $myName"

Variable Type Casting

Highlights:Declaring a variable without specifying the data type.Arithmetic Operators in PowerShellDemosteps:

Step 1: Variables in PowerShell are weakly typed by default, they can contain any kind of data.

variable type casting — Variable Type Casting in PowerShell

Step 2: The addition of two such variables, where one contains a string and the other contains a number depends on the order in which you add the variables.

type casting examples — PowerShell Variable Type Casting Example

Step 3: This can be avoided by casting the variable with the expected data type.

casting the data types — Variable Type Casting Using Data Types

Step 4: PowerShell helps to perform mathematical functions and calculations on variabes using arithmetic operators.

PowerShell processes the operators in the following precedence order:
- Parentheses(), – negative number, *, /, %, “+ or –”
The expressions are processed from left to right according to the precedence rules.

PowerShell Variables Data Types

[int] 32-bit signed integer
[long] 64-bit signed integer
[string] Fixed-length string of characters
[char] 16-bit character
[bool] True/false value
[byte] 8-bit integer
[double] Double-precision 64-bit floating point number
[decimal] 128-bit decimal value
[single] Single-precision 32-bit floating point number
[array] List of similar values

PowerShell Automatic Variables

Source – Microsoft

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