Explore PowerShell (7) PowerShell Variables

Variable

In program design, variables are the most basic concept. They are the codes used to represent data during storage. In PowerShell, variables are usually used in scripts. They can be numbers, characters, strings, and even objects. Of course, like any shell, it also has its own specific variables, such as $ _, $ Args, $ Error, $ Home, and $ PSHome.

In PowerShell, all variables start with "$" and use "=" to assign values to variables. For example:

$StrUser = “MR″ <enter> 

Or run the "set-variable" command:

set-variable -name StrUser -value “MaRui” <enter> 

Note that you do not need to use "$" before the variable name when using the "set-variable" command ".

Of course, some special names should be avoided when declaring variables. These names are called "system reserved words" and are listed as follows:

Break | continue | do | else | elseif | filter | foreach | function | if | in | return | switch | until | where | while

Screen output variable value:

write-output $StrUser <enter> 

Or directly enter the variable name, such:

$StrUser <enter> 

Running result:

Character, string

Similar to program design, data types must be clarified when processing characters and strings. The following describes common PowerShell data types:

Data types used by PowerShell

Int	Signed, 32bit
Long	Signed, 64bit
Double	Double Precision 64-bit floating point
Single	32-bit floating point
String	Unicode encoded string
Char	Unicode encoded character, 16 Bit
Byte	Unsigned character, 8bit
Decimal	Decimal number, 128bit
Array	Array
Xml	Xml Object
Hashtable	Hash table
Bool	True and false

We use several examples to understand the meaning of data types. First, let's look at the string example:

$strA = “Hello “ <enter>  
$strB = “World!” <enter>  
$strC = $strA + $strB <enter>  
$strC <enter> 

There are other methods for string operations, such:

Replace

$strA = “hi! world!” <enter>  
$strB = $strA -replace “hi!”, “Hello” <enter>  
$strB <enter> 

Reference

Take a look at the following example:

$strA = “MaRui” <enter>  
"This is $strA.” <enter>  
'This is $strA.' <enter> 

In PowerShell, it is very simple to operate a number without too much explanation. There are only a few examples:

5 + 100 <enter>  
$x=200+1 <enter>  
$x <enter>  
[int]$y=(7 + 13 * 2) / 10 <enter>
$y <enter> 

Sometimes, PowerShell cannot automatically specify the data type for us. Therefore, when writing a script, declare the data type for the variable as much as possible to prevent errors. The following operations are performed on mathematical operations:

+	Add
-	Subtraction
*	Multiplication
/	Division
%	Remainder
=	Assignment
++	Add 1 to the variable, equivalent to + 1
--	Subtract 1 from the variable, which is equivalent to-1.

Of course, parentheses are inevitable.